Tid Bits. Should we be concerned about over reving our Olds engines.

[Bob Dunahugh]

The stock 455 that we have is good to 5000 RPM's. The stock 403 is fine t=
o 6000 RPM's. But with the cam profiles that our engines have. There is no=
reason to go much be on 3900 RPMs. Engine cam profiles are based on many=
factors. But mostly on how the engine is going to be used, engine cubic in=
ches, final drive ratio, tire diameter, and expected gross weight to be mov=
ed. There are more. But these are the main ones. GM had to make a car engi=
ne perform the duties of a truck engine. Our engine were built to produce i=
t's peak horsepower, and torque in the 2400, to 2800 RPM range. We drive to=
rque. Not horsepower. Torque is what gets us up that next hill. A torque ch=
art starts at 600 RPM's. And continues to climb till the engine hits it's p=
eak torque RPM point. Then the torque produced will state to drop off. The =
torque curve chart will be in the shape of a bell. The cam shaft lob profi=
le is the magic that make our engines able to perform to move us along so w=
ell. Whenever I start climbing long steep grades. Sift to second. Run the =
RPM's up to 3700, to 4000 RPM's till I get to the top. And never have the =
throttle more then half open. I have a personal game I play. In trying to s=
ee how high I can get the number of cars that I can get to go around me bef=
ore I get to the top of the pass. ( GRIN ) When someone says that any RPM'=
s over 3300 RPM's. will just burn the engine up. Due to high piston speeds=
. That is absolutely, positively not true. Bob Dunahugh 78 Royale

 

[justin brady1]

Glad to know someone is doing it that way!
Makes me nervous to rev over 3k!

That being said I've never had a hill that I have any trouble at all getting up, sometimes in second bur normally in 3rd.
I've never revved mine over 3100 and never had an issue.
Maybe next time I;ll rev it up for the hell of it!
--
Justin Brady
http://www.thegmcrv.com/
1976 Palm Beach 455

 

[Jim Hupy]

I just used a quick 'n dirty formula and figured both 455 and 403 engines
piston speed in surface feet per minute. Most engine builders agree that
you can safely run an engine under average load at 5000 surface per minute.
Neither 455 engines nor 403's come anywhere near that speed at 4000
rpm. 455 =2833.3 sfm vs 403 = 2256.6 sfm.
Bob is correct, don't worry about over revving either engine. If you really
want to worry about something, worry about lugging your engine and not keep
its oiling system full.
Jim Hupy

> Glad to know someone is doing it that way!
> Makes me nervous to rev over 3k!
>
> That being said I've never had a hill that I have any trouble at all
> getting up, sometimes in second bur normally in 3rd.
> I've never revved mine over 3100 and never had an issue.
> Maybe next time I;ll rev it up for the hell of it!
> --
> Justin Brady
> http://www.thegmcrv.com/
> 1976 Palm Beach 455
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[john phillips]

Do most of you have tacks to see how fast you are running?
I would think as light as our coaches are unless we are towing we should be
able to keep up with the big heavy diesel pushers.
I have driven mine about 300 miles total and none of it in hills. Just
looking at the horsepower ratings and weight I should have more power per
pound than a 400 horse 32000 lb SOB.
Am I wrong? I would think this should climb more like a minivan with a
small engine. Is the problem that we really need a 5-speed transmission
with a gear between each of what we have?

> I just used a quick 'n dirty formula and figured both 455 and 403 engines
> piston speed in surface feet per minute. Most engine builders agree that
> you can safely run an engine under average load at 5000 surface per minute.
> Neither 455 engines nor 403's come anywhere near that speed at 4000
> rpm. 455 =2833.3 sfm vs 403 = 2256.6 sfm.
> Bob is correct, don't worry about over revving either engine. If you really
> want to worry about something, worry about lugging your engine and not keep
> its oiling system full.
> Jim Hupy
>

>
> > Glad to know someone is doing it that way!
> > Makes me nervous to rev over 3k!
> >
> > That being said I've never had a hill that I have any trouble at all
> > getting up, sometimes in second bur normally in 3rd.
> > I've never revved mine over 3100 and never had an issue.
> > Maybe next time I;ll rev it up for the hell of it!
> > --
> > Justin Brady
> > http://www.thegmcrv.com/
> > 1976 Palm Beach 455
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--

*John Phillips*

 

[Matt Colie]

> Do most of you have tacks to see how fast you are running?
> I would think as light as our coaches are unless we are towing we should be able to keep up with the big heavy diesel pushers.
> I have driven mine about 300 miles total and none of it in hills. Just looking at the horsepower ratings and weight I should have more power per
> pound than a 400 horse 32000 lb SOB.
> Am I wrong? I would think this should climb more like a minivan with a small engine. Is the problem that we really need a 5-speed transmission
> with a gear between each of what we have?
>
> *John Phillips*

John,

Very few of us have tachometers. I do because I am an engine dweeb and have been since about age 10. I made a living at it since then, and have a
lot of experience to offer.

Multi-speed transmission lore is an adjunct of the emissions age. OK, Model Ts had a 2 speed system but a top speed of about 45. Other than that
(and the two speed early automatics) the world has gotten by with three speed transmissions until we tried to beat the little horseys harder and found
that the ran better when bred for a narrow performance band. The Oldsmobile engines of the coach period are not those. They are not quarter horses
that can want to go for a sprint, they are the Percherons and Clydesdales of the passcar engine world. Even as big as they are, they still are not
steam engines that do maximum torque at zero speed. They ask for help there. When these coaches went out on the road, gas was relatively in
expensive and the speed limits in most states were 65~70. Then came the Carter/Arab oil embargo......

The coaches had launched with the 3.07 rear end (final drive, ours isn't in the rear). Even at 70, that is a little low, but it was what GM had in
inventory from the Toronado towing package. It was accepted based on the original 19 and 22 foot models. It was actually wrong then. Now the
situation is worse. Twenty-Three footers are rare and the 26s can tip a scale at #12,000+.

My coach is a very light 23. With the stock cam, it suffered at 60~65. That was 21~2200 with the converter slip (it is not fully engaged at those
road speeds). The engine was not comfortable, but it was not happy either for the 70K+ miles we drove here. Last year, she failed a piston. I
believe it was a result of having to run at low piston speeds with high BMEP, but that is just an expert's opinion. Now, she has a new cam (thanks to
Dick Paterson recommendation) and is happy at the too low speed such that she doesn't like running there (and will tell you, if you listen) but she is
more comfortable.

As soon as the situation allows, I am going to install a 3.55. Remember, she is a 9400# coach. A 3.42 (old GM number) would be marginally better
than stock, but not quite there for this weight. If you have a later build and it will be heavier, I very seriously suggest that you thing about
spring for a 3.70 before you do anything else. If the coach is a 403, you should really consider it before the next oil change.

Even before getting the correct cam, we could keep up with the monster coaches over the Big Horn (9200MSL fron GPS) and pass some little J-cars at
~8500MSL. We do loose out at about 10KMSL because the diesels are all turbocharged (don't think I haven't thought about that) but the final drive
would still be wrong).

That is this dyno-lab refugee and 14 year GMC owner's take on the whole thing. But you are free to waste your money where you please. (JimK is the
source to the high number final drives and I have no interest in that situation.)

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

 

[Bob Dunahugh]

The best way to get to the top of the mountain. Several years ago. I was=
climbing out of Denver. Up to the Eisenhower tunnel. That's a long steep=
climb. While pulling one of my Yenko's on a trailer. With a GVW of 17,000 =
LBS. 3:70 FD, and a 403. I put the trans in first. Ran the 403 up to 4400=
RPM's. Then used no more the half throttle. As for speed. Got what I got. =
Didn't care. So what was going on here. First. With half throttle. I was re=
ducing the amount of BTU's going into the engine. With the RPM's up. The en=
gine water pump was taking more engine heat to the radiator. The engine fa=
n was pulling more air in to keep the engine cooler. The trans fluid pump =
was also caring more heat off to the trans cooler. Jim Hupy's e-mail covere=
d piston FPM well. GM should have never installed a 3:07 FD in these GMC'=
s that weigh 11,000 lbs. The 3:21, 3;42, 3:55 are of alittle help. Towing o=
r not. The 3:70 has been proven to be the best choice. Also with gas milea=
ge going up. Because your running a higher intake manifold vacuum. Bob Du=
nahugh 78 Royale ________________________________ From: Bob Dunahugh=
Sent: Thursday, January 24, 2019 10:40 PM To: gmclist=
Subject: Tid Bits. Should we be concerned about over reving our Olds eng=
ines. The stock 455 that we have is good to 5000 RPM's. The stock 40=
3 is fine to 6000 RPM's. But with the cam profiles that our engines have. =
There is no reason to go much be on 3900 RPMs. Engine cam profiles are ba=
sed on many factors. But mostly on how the engine is going to be used, engi=
ne cubic inches, final drive ratio, tire diameter, and expected gross weigh=
t to be moved. There are more. But these are the main ones. GM had to make =
a car engine perform the duties of a truck engine. Our engine were built t=
o produce it's peak horsepower, and torque in the 2400, to 2800 RPM range. =
We drive torque. Not horsepower. Torque is what gets us up that next hill. =
A torque chart starts at 600 RPM's. And continues to climb till the engine =
hits it's peak torque RPM point. Then the torque produced will state to dro=
p off. The torque curve chart will be in the shape of a bell. The cam shaf=
t lob profile is the magic that make our engines able to perform to move us=
along so well. Whenever I start climbing long steep grades. Sift to secon=
d. Run the RPM's up to 3700, to 4000 RPM's till I get to the top. And neve=
r have the throttle more then half open. I have a personal game I play. In =
trying to see how high I can get the number of cars that I can get to go ar=
ound me before I get to the top of the pass. ( GRIN ) When someone says th=
at any RPM's over 3300 RPM's. will just burn the engine up. Due to high pi=
ston speeds. That is absolutely, positively not true. Bob Dunahugh 78 Ro=
yale

 

[roy keen]

I wouldn't be without a tack and I wouldn't run a 455 at or above 4000 rpm for any length of time especially in these western mountains with the pedal
to the metal. If you do and the motor wasn't modified for high rpm you may be sorry you did.3000 is a lot safer.
--
Roy Keen
Minden,NV
76 X Glenbrook

 

[Jim Hupy]

I have four extra gages on my 78 Royale 403. Vacuum, Tachometer,
Transmission fluid temperature at the Ragusa finned aluminum pan, and final
drive oil temperature. The Tachometer and Vacuum gage are mounted between
the drivers side windshield and the horse collar that surrounds the dash.
The oil gages are mounted where the ash tray used to be.
I often run my 403 between 3000 and 3600 rpm. With the final drive
and wheel and tire combinations that I run, that is between 62 and 75 miles
per hour. The 403 is a happy camper in that rpm range.
The 455 will not be hurt a bit at those rpms either.
If I am climbing long continuous grades, I will manually downshift and
run the 403 at 4200 - 4500 rpm at 10 to 12 inches of mercury ( throttles
1/2 way open) for long stretches. My original engine is still equipped with
a quadrajet carb and Doug Thorley Coated headers, dual mufflers and a 2
3/4" tail pipe. It has over 130,000 miles and burns a quart of 20 -50
Valvoline Dino oil in about 1500 miles. Last time I checked compression, it
pumped over 150 psi across the board. I can't complain about that
performance. The best modification I ever did was the 3:70 final drive
gearing.
Jim Hupy

> I wouldn't be without a tack and I wouldn't run a 455 at or above 4000 rpm
> for any length of time especially in these western mountains with the pedal
> to the metal. If you do and the motor wasn't modified for high rpm you may
> be sorry you did.3000 is a lot safer.
> --
> Roy Keen
> Minden,NV
> 76 X Glenbrook
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[john phillips]

Matt

> I have the original Avion VIN A26000 with a GMC Firewall VIN of
> TZE064V10116 with a 455 and headers. Given that our drive wheels are
> about 15% larger than the car version the 3.07 would be like having a 2.60
> in the Toronado towing package. Not much of a towing package. So unless you
> are going to do a lot of flatland 80 mph driving in a very light coach a
> higher final drive ratio would be in order. A 3.53 would match the Toronado
> towing package . Will a higher final drive ratio take some of the strain
> off of the transmission and the rest of the drivetrain?

* My coach is a very light 23. With the stock cam, it suffered at 60~65.
That was 21~2200 with the converter slip (it is not fully engaged at those*
*road speeds). *
Are you implying that you need more RPMs to get the torque converter to
lock up/not slip? Is there a lockup clutch in our converter?

> I have four extra gages on my 78 Royale 403. Vacuum, Tachometer,
> Transmission fluid temperature at the Ragusa finned aluminum pan, and final
> drive oil temperature. The Tachometer and Vacuum gage are mounted between
> the drivers side windshield and the horse collar that surrounds the dash.
> The oil gages are mounted where the ash tray used to be.
> I often run my 403 between 3000 and 3600 rpm. With the final drive
> and wheel and tire combinations that I run, that is between 62 and 75 miles
> per hour. The 403 is a happy camper in that rpm range.
> The 455 will not be hurt a bit at those rpms either.
> If I am climbing long continuous grades, I will manually downshift and
> run the 403 at 4200 - 4500 rpm at 10 to 12 inches of mercury ( throttles
> 1/2 way open) for long stretches. My original engine is still equipped with
> a quadrajet carb and Doug Thorley Coated headers, dual mufflers and a 2
> 3/4" tail pipe. It has over 130,000 miles and burns a quart of 20 -50
> Valvoline Dino oil in about 1500 miles. Last time I checked compression, it
> pumped over 150 psi across the board. I can't complain about that
> performance. The best modification I ever did was the 3:70 final drive
> gearing.
> Jim Hupy
>

>
> > I wouldn't be without a tack and I wouldn't run a 455 at or above 4000
> rpm
> > for any length of time especially in these western mountains with the
> pedal
> > to the metal. If you do and the motor wasn't modified for high rpm you
> may
> > be sorry you did.3000 is a lot safer.
> > --
> > Roy Keen
> > Minden,NV
> > 76 X Glenbrook
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--

*John Phillips*

 

[Matt Colie]

> Matt
>
> > I have the original Avion VIN A26000 with a GMC Firewall VIN of
> > TZE064V10116 with a 455 and headers. Given that our drive wheels are
> > about 15% larger than the car version the 3.07 would be like having a 2.60
> > in the Toronado towing package. Not much of a towing package. So unless you
> > are going to do a lot of flatland 80 mph driving in a very light coach a
> > higher final drive ratio would be in order. A 3.53 would match the Toronado
> > towing package . Will a higher final drive ratio take some of the strain
> > off of the transmission and the rest of the drivetrain?
>
> * My coach is a very light 23. With the stock cam, it suffered at 60~65.
> That was 21~2200 with the converter slip (it is not fully engaged at those*
> *road speeds). *
> Are you implying that you need more RPMs to get the torque converter to
> lock up/not slip? Is there a lockup clutch in our converter?

Yes John,

That is exactly what I am saying and there was no lock-up version of torque converter for transmissions of this era. That did not come along until
CAFE hit the scene. (Unless you were brave enough to try to drive a street car with a "Clutch-Flyt".

Matt

Quote:

>
> > I have four extra gages on my 78 Royale 403. Vacuum, Tachometer,
> > Transmission fluid temperature at the Ragusa finned aluminum pan, and final
> > drive oil temperature. The Tachometer and Vacuum gage are mounted between
> > the drivers side windshield and the horse collar that surrounds the dash.
> > The oil gages are mounted where the ash tray used to be.
> > I often run my 403 between 3000 and 3600 rpm. With the final drive
> > and wheel and tire combinations that I run, that is between 62 and 75 miles
> > per hour. The 403 is a happy camper in that rpm range.
> > The 455 will not be hurt a bit at those rpms either.
> > If I am climbing long continuous grades, I will manually downshift and
> > run the 403 at 4200 - 4500 rpm at 10 to 12 inches of mercury ( throttles
> > 1/2 way open) for long stretches. My original engine is still equipped with
> > a quadrajet carb and Doug Thorley Coated headers, dual mufflers and a 2
> > 3/4" tail pipe. It has over 130,000 miles and burns a quart of 20 -50
> > Valvoline Dino oil in about 1500 miles. Last time I checked compression, it
> > pumped over 150 psi across the board. I can't complain about that
> > performance. The best modification I ever did was the 3:70 final drive
> > gearing.
> > Jim Hupy
> >
> > On Sat, Jan 26, 2019, 9:21 AM roy keen
> >> I wouldn't be without a tack and I wouldn't run a 455 at or above 4000
> > rpm
> >> for any length of time especially in these western mountains with the
> > pedal
> >> to the metal. If you do and the motor wasn't modified for high rpm you
> > may
> >> be sorry you did.3000 is a lot safer.
> >> --
> >> Roy Keen
> >> Minden,NV
> >> 76 X Glenbrook
> >>
> >> _______________________________________________
> >> GMCnet mailing list
> >> Unsubscribe or Change List Options:
> >> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >>
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
>
>
> --
>
> *John Phillips*
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit

 

[Jim Hupy]

Depending upon whether or not your torque converter is original or has been
upgraded, you probably have a converter with a 2500 rpm stall speed. That
is NOT TO SAY THAT IT "LOCKS UP" because it never really does that. There
is always some slippage between engine speed and transmission input shaft
speed.
A true "lock up" converter is the same as a manual clutch (very little
slippage).
So, at 2100 rpm, your engine is turning faster than your transmission
input shaft, and some heating of the transmission fluid is occurring as a
result of that slippage. Engineers have to account for energy loss through
moving something by applying a force (work) or by heat loss.
Jim Hupy

> > Matt
> >
> > > I have the original Avion VIN A26000 with a GMC Firewall VIN of
> > > TZE064V10116 with a 455 and headers. Given that our drive wheels are
> > > about 15% larger than the car version the 3.07 would be like having a
> 2.60
> > > in the Toronado towing package. Not much of a towing package. So
> unless you
> > > are going to do a lot of flatland 80 mph driving in a very light
> coach a
> > > higher final drive ratio would be in order. A 3.53 would match the
> Toronado
> > > towing package . Will a higher final drive ratio take some of the
> strain
> > > off of the transmission and the rest of the drivetrain?
> >
> > * My coach is a very light 23. With the stock cam, it suffered at 60~65.
> > That was 21~2200 with the converter slip (it is not fully engaged at
> those*
> > *road speeds). *
> > Are you implying that you need more RPMs to get the torque converter to
> > lock up/not slip? Is there a lockup clutch in our converter?
>
> Yes John,
>
> That is exactly what I am saying and there was no lock-up version of
> torque converter for transmissions of this era. That did not come along
> until
> CAFE hit the scene. (Unless you were brave enough to try to drive a street
> car with a "Clutch-Flyt".
>
> Matt
>
> Quote:

> >
> > > I have four extra gages on my 78 Royale 403. Vacuum, Tachometer,
> > > Transmission fluid temperature at the Ragusa finned aluminum pan, and
> final
> > > drive oil temperature. The Tachometer and Vacuum gage are mounted
> between
> > > the drivers side windshield and the horse collar that surrounds the
> dash.
> > > The oil gages are mounted where the ash tray used to be.
> > > I often run my 403 between 3000 and 3600 rpm. With the final
> drive
> > > and wheel and tire combinations that I run, that is between 62 and 75
> miles
> > > per hour. The 403 is a happy camper in that rpm range.
> > > The 455 will not be hurt a bit at those rpms either.
> > > If I am climbing long continuous grades, I will manually
> downshift and
> > > run the 403 at 4200 - 4500 rpm at 10 to 12 inches of mercury (
> throttles
> > > 1/2 way open) for long stretches. My original engine is still
> equipped with
> > > a quadrajet carb and Doug Thorley Coated headers, dual mufflers and a
> 2
> > > 3/4" tail pipe. It has over 130,000 miles and burns a quart of 20 -50
> > > Valvoline Dino oil in about 1500 miles. Last time I checked
> compression, it
> > > pumped over 150 psi across the board. I can't complain about that
> > > performance. The best modification I ever did was the 3:70 final drive
> > > gearing.
> > > Jim Hupy
> > >
> > > On Sat, Jan 26, 2019, 9:21 AM roy keen
> > >> I wouldn't be without a tack and I wouldn't run a 455 at or above
> 4000
> > > rpm
> > >> for any length of time especially in these western mountains with the
> > > pedal
> > >> to the metal. If you do and the motor wasn't modified for high rpm
> you
> > > may
> > >> be sorry you did.3000 is a lot safer.
> > >> --
> > >> Roy Keen
> > >> Minden,NV
> > >> 76 X Glenbrook
> > >>
> > >> _______________________________________________
> > >> GMCnet mailing list
> > >> Unsubscribe or Change List Options:
> > >> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> > >>
> > > _______________________________________________
> > > GMCnet mailing list
> > > Unsubscribe or Change List Options:
> > > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> > >
> >
> >
> > --
> >
> > *John Phillips*
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Electronically Controlled Quiet Engine Cooling Fan
> OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[kosier]

Matt,

Have you checked the Packard Ultramatic of the mid 50s? I overhauled one
back in the early 60s and I seem to recall a clutch in the converter.

Gary Kosier

> Yes John,
>
> That is exactly what I am saying and there was no lock-up version of
> torque converter for transmissions of this era. That did not come along
> until
> CAFE hit the scene. (Unless you were brave enough to try to drive a street
> car with a "Clutch-Flyt".
>
> Matt
>
> Quote:

>>
>> > I have four extra gages on my 78 Royale 403. Vacuum, Tachometer,
>> > Transmission fluid temperature at the Ragusa finned aluminum pan, and
>> > final
>> > drive oil temperature. The Tachometer and Vacuum gage are mounted
>> > between
>> > the drivers side windshield and the horse collar that surrounds the
>> > dash.
>> > The oil gages are mounted where the ash tray used to be.
>> > I often run my 403 between 3000 and 3600 rpm. With the final
>> > drive
>> > and wheel and tire combinations that I run, that is between 62 and 75
>> > miles
>> > per hour. The 403 is a happy camper in that rpm range.
>> > The 455 will not be hurt a bit at those rpms either.
>> > If I am climbing long continuous grades, I will manually
>> > downshift and
>> > run the 403 at 4200 - 4500 rpm at 10 to 12 inches of mercury (
>> > throttles
>> > 1/2 way open) for long stretches. My original engine is still equipped
>> > with
>> > a quadrajet carb and Doug Thorley Coated headers, dual mufflers and a
>> > 2
>> > 3/4" tail pipe. It has over 130,000 miles and burns a quart of 20 -50
>> > Valvoline Dino oil in about 1500 miles. Last time I checked
>> > compression, it
>> > pumped over 150 psi across the board. I can't complain about that
>> > performance. The best modification I ever did was the 3:70 final drive
>> > gearing.
>> > Jim Hupy
>> >
>> > On Sat, Jan 26, 2019, 9:21 AM roy keen
>> >> I wouldn't be without a tack and I wouldn't run a 455 at or above
>> >> 4000
>> > rpm
>> >> for any length of time especially in these western mountains with the
>> > pedal
>> >> to the metal. If you do and the motor wasn't modified for high rpm
>> >> you
>> > may
>> >> be sorry you did.3000 is a lot safer.
>> >> --
>> >> Roy Keen
>> >> Minden,NV
>> >> 76 X Glenbrook
>> >>
>> >> _______________________________________________
>> >> GMCnet mailing list
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>>
>> --
>>
>> *John Phillips*
>> _______________________________________________
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>
>
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Electronically Controlled Quiet Engine Cooling Fan
> OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
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[d c *mac* macdonald]

Hi, Jim!

It my reasoning is correct about stall speed, we would improve overall performance if we choose a final drive ratio that would our RPM at least at torque converter stall speed at say 55-60 MPH?

Mac Macdonald in OKC
The Money Pit
76 ex Palm Beac

Sent from my iPhone

Depending upon whether or not your torque converter is original or has been
upgraded, you probably have a converter with a 2500 rpm stall speed. That
is NOT TO SAY THAT IT "LOCKS UP" because it never really does that. There
is always some slippage between engine speed and transmission input shaft
speed.
A true "lock up" converter is the same as a manual clutch (very little
slippage).
So, at 2100 rpm, your engine is turning faster than your transmission
input shaft, and some heating of the transmission fluid is occurring as a
result of that slippage. Engineers have to account for energy loss through
moving something by applying a force (work) or by heat loss.
Jim Hupy

>

>> Matt
>>
>>> I have the original Avion VIN A26000 with a GMC Firewall VIN of
>>> TZE064V10116 with a 455 and headers. Given that our drive wheels are
>>> about 15% larger than the car version the 3.07 would be like having a
> 2.60
>>> in the Toronado towing package. Not much of a towing package. So
> unless you
>>> are going to do a lot of flatland 80 mph driving in a very light
> coach a
>>> higher final drive ratio would be in order. A 3.53 would match the
> Toronado
>>> towing package . Will a higher final drive ratio take some of the
> strain
>>> off of the transmission and the rest of the drivetrain?
>>
>> * My coach is a very light 23. With the stock cam, it suffered at 60~65.
>> That was 21~2200 with the converter slip (it is not fully engaged at
> those*
>> *road speeds). *
>> Are you implying that you need more RPMs to get the torque converter to
>> lock up/not slip? Is there a lockup clutch in our converter?
>
> Yes John,
>
> That is exactly what I am saying and there was no lock-up version of
> torque converter for transmissions of this era. That did not come along
> until
> CAFE hit the scene. (Unless you were brave enough to try to drive a street
> car with a "Clutch-Flyt".
>
> Matt
>
> Quote:

>>>
>>> I have four extra gages on my 78 Royale 403. Vacuum, Tachometer,
>>> Transmission fluid temperature at the Ragusa finned aluminum pan, and
> final
>>> drive oil temperature. The Tachometer and Vacuum gage are mounted
> between
>>> the drivers side windshield and the horse collar that surrounds the
> dash.
>>> The oil gages are mounted where the ash tray used to be.
>>> I often run my 403 between 3000 and 3600 rpm. With the final
> drive
>>> and wheel and tire combinations that I run, that is between 62 and 75
> miles
>>> per hour. The 403 is a happy camper in that rpm range.
>>> The 455 will not be hurt a bit at those rpms either.
>>> If I am climbing long continuous grades, I will manually
> downshift and
>>> run the 403 at 4200 - 4500 rpm at 10 to 12 inches of mercury (
> throttles
>>> 1/2 way open) for long stretches. My original engine is still
> equipped with
>>> a quadrajet carb and Doug Thorley Coated headers, dual mufflers and a
> 2
>>> 3/4" tail pipe. It has over 130,000 miles and burns a quart of 20 -50
>>> Valvoline Dino oil in about 1500 miles. Last time I checked
> compression, it
>>> pumped over 150 psi across the board. I can't complain about that
>>> performance. The best modification I ever did was the 3:70 final drive
>>> gearing.
>>> Jim Hupy
>>>
>>> On Sat, Jan 26, 2019, 9:21 AM roy keen
>>>> I wouldn't be without a tack and I wouldn't run a 455 at or above
> 4000
>>> rpm
>>>> for any length of time especially in these western mountains with the
>>> pedal
>>>> to the metal. If you do and the motor wasn't modified for high rpm
> you
>>> may
>>>> be sorry you did.3000 is a lot safer.
>>>> --
>>>> Roy Keen
>>>> Minden,NV
>>>> 76 X Glenbrook
>>>>
>>>> _______________________________________________
>>>> GMCnet mailing list
>>>> Unsubscribe or Change List Options:
>>>> https://apc01.safelinks.protection.outlook.com/?url=http%3A%2F%2Flist.gmcnet.org%2Fmailman%2Flistinfo%2Fgmclist_list.gmcnet.org&data=02%7C01%7C%7C7c770bac075c41cc84b208d6846e6627%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636842007023353764&sdata=oEOuMRm96pVz9yQi80zXZFTJWwQuPaaHoPmj%2BJTAnBQ%3D&reserved=0
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
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>>
>>
>> --
>>
>> *John Phillips*
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
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>
>
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Electronically Controlled Quiet Engine Cooling Fan
> OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> https://apc01.safelinks.protection.outlook.com/?url=http%3A%2F%2Flist.gmcnet.org%2Fmailman%2Flistinfo%2Fgmclist_list.gmcnet.org&data=02%7C01%7C%7C7c770bac075c41cc84b208d6846e6627%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636842007023353764&sdata=oEOuMRm96pVz9yQi80zXZFTJWwQuPaaHoPmj%2BJTAnBQ%3D&reserved=0
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[bob heller]

"That is exactly what I am saying and there was no lock-up version of torque converter for transmissions of this era. That did not come along until
CAFE hit the scene."

I seem to remember that Studebaker had a lockup torque converter decades ago, so a bit of Googling found this article which, in part, says:

Lockup clutches were used in some nonautomotive torque converters before World War II, but the first regular-production automotive application was the
1949 Packard Ultramatic Drive, which established a model for subsequent transmission designs. It was followed in fairly short order by the 1950
Studebaker Automatic Drive, which took a somewhat different approach to the same problem.

https://ateupwithmotor.com/terms-technology-definitions/split-torque-lockup-converters/?cookie-state-change=1548616977986

Correct me if I am wrong but 1949 and 1950 was waaaaaay before the CAFE age (law was enacted by Congress in 1975). For some reason I always insist on
accurate data. If this article about Studebaker and Packard transmissions is inaccurate please let me know.

While I sometimes wish my GMC had a wider spread of gear ratios, I would think a lockup converter would be a benefit while cruising at light to
moderate loads.
--
Bob Heller
1974 X-Canyonlands 26ft
Original 455 exc for timing chain,
Rockwell intake, valve covers. 145k miles.
Winter Springs FL

 

[jim kanomata1]

If your nervous going over 3,000rpm, your off page in your experience with
engines.
There are times when I'm passing at hwy speeds when I will reve 4,500 for
short duration .
Back in the 90's there were lot of guys that knew engines and they inspired
me to move the gear ratio to 3.70.
Lock up converters we used in the 90's and did not really see any
worthwhile gains.
I and 15 other owners are running the 4.10 ratio with good results.
Opinions are good but my experience and feedback is hard to beat as we have
sold over 3,000 3.70 and get very good feedback.455 does better with 3.70
and have seen noticeable poor result with 3.55 and 3.42.
We're the only one that carry a 50,000 mile warranty .

> "That is exactly what I am saying and there was no lock-up version of
> torque converter for transmissions of this era. That did not come along
> until
> CAFE hit the scene."
>
>
> I seem to remember that Studebaker had a lockup torque converter decades
> ago, so a bit of Googling found this article which, in part, says:
>
> Lockup clutches were used in some nonautomotive torque converters before
> World War II, but the first regular-production automotive application was
> the
> 1949 Packard Ultramatic Drive, which established a model for subsequent
> transmission designs. It was followed in fairly short order by the 1950
> Studebaker Automatic Drive, which took a somewhat different approach to
> the same problem.
>
>
>
> https://ateupwithmotor.com/terms-technology-definitions/split-torque-lockup-converters/?cookie-state-change=1548616977986
>
> Correct me if I am wrong but 1949 and 1950 was waaaaaay before the CAFE
> age (law was enacted by Congress in 1975). For some reason I always insist
> on
> accurate data. If this article about Studebaker and Packard transmissions
> is inaccurate please let me know.
>
> While I sometimes wish my GMC had a wider spread of gear ratios, I would
> think a lockup converter would be a benefit while cruising at light to
> moderate loads.
> --
> Bob Heller
> 1974 X-Canyonlands 26ft
> Original 455 exc for timing chain,
> Rockwell intake, valve covers. 145k miles.
> Winter Springs FL
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.appliedgmc.com
1-800-752-7502

 

[Jim Hupy]

Mac, to answer your lock up question, yes "BUT" it depends. Lockup means
several things depending upon whether it is a full mechanical lockup type,
or a hydraulic lockup type. The hydraulic type still slips a bit, and is
smoother in operation. Quieter, too.
Yes, but if it locks up below the usable torque curve, it might lug
the engine. Just what it does, there are no perfect torque converters, only
ones that work a few percentage points better than the others.
Jim Hupy

> If your nervous going over 3,000rpm, your off page in your experience with
> engines.
> There are times when I'm passing at hwy speeds when I will reve 4,500 for
> short duration .
> Back in the 90's there were lot of guys that knew engines and they inspired
> me to move the gear ratio to 3.70.
> Lock up converters we used in the 90's and did not really see any
> worthwhile gains.
> I and 15 other owners are running the 4.10 ratio with good results.
> Opinions are good but my experience and feedback is hard to beat as we have
> sold over 3,000 3.70 and get very good feedback.455 does better with 3.70
> and have seen noticeable poor result with 3.55 and 3.42.
> We're the only one that carry a 50,000 mile warranty .
>

>
> > "That is exactly what I am saying and there was no lock-up version of
> > torque converter for transmissions of this era. That did not come along
> > until
> > CAFE hit the scene."
> >
> >
> > I seem to remember that Studebaker had a lockup torque converter decades
> > ago, so a bit of Googling found this article which, in part, says:
> >
> > Lockup clutches were used in some nonautomotive torque converters before
> > World War II, but the first regular-production automotive application was
> > the
> > 1949 Packard Ultramatic Drive, which established a model for subsequent
> > transmission designs. It was followed in fairly short order by the 1950
> > Studebaker Automatic Drive, which took a somewhat different approach to
> > the same problem.
> >
> >
> >
> >
> https://ateupwithmotor.com/terms-technology-definitions/split-torque-lockup-converters/?cookie-state-change=1548616977986
> >
> > Correct me if I am wrong but 1949 and 1950 was waaaaaay before the CAFE
> > age (law was enacted by Congress in 1975). For some reason I always
> insist
> > on
> > accurate data. If this article about Studebaker and Packard transmissions
> > is inaccurate please let me know.
> >
> > While I sometimes wish my GMC had a wider spread of gear ratios, I would
> > think a lockup converter would be a benefit while cruising at light to
> > moderate loads.
> > --
> > Bob Heller
> > 1974 X-Canyonlands 26ft
> > Original 455 exc for timing chain,
> > Rockwell intake, valve covers. 145k miles.
> > Winter Springs FL
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk
> http://www.appliedgmc.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[adolph santorine]

We have a boat we play with on the Ohio River.

It’s an 8.1 liter (496 cubic Inch) big block Chevrolet

It’s perfectly happy making 4800 RPM (what boaters describe at WOT) for hours on end.

Of course, it does so while making 460 horsepower or so, and drinking an appropriate amount of fuel.

35 gallons per hour with a 100 gallon fuel tank.

Let’s just say I don’t run at that power setting often.

I remind other pilots that boaters have $100 hamburgers as well.

Dolph

DE AD0LF

Wheeling, West Virginia

1977 26’ ex-PalmBeach
Howell EFI & EBL, Reaction Arms, Sullybilt Bags, Manny Transmission

“The Aluminum and Fiberglass Mistress"

>
> If your nervous going over 3,000rpm, your off page in your experience with
> engines.
> There are times when I'm passing at hwy speeds when I will reve 4,500 for
> short duration .
> Back in the 90's there were lot of guys that knew engines and they inspired
> me to move the gear ratio to 3.70.
> Lock up converters we used in the 90's and did not really see any
> worthwhile gains.
> I and 15 other owners are running the 4.10 ratio with good results.
> Opinions are good but my experience and feedback is hard to beat as we have
> sold over 3,000 3.70 and get very good feedback.455 does better with 3.70
> and have seen noticeable poor result with 3.55 and 3.42.
> We're the only one that carry a 50,000 mile warranty .
>

>
>> "That is exactly what I am saying and there was no lock-up version of
>> torque converter for transmissions of this era. That did not come along
>> until
>> CAFE hit the scene."
>>
>>
>> I seem to remember that Studebaker had a lockup torque converter decades
>> ago, so a bit of Googling found this article which, in part, says:
>>
>> Lockup clutches were used in some nonautomotive torque converters before
>> World War II, but the first regular-production automotive application was
>> the
>> 1949 Packard Ultramatic Drive, which established a model for subsequent
>> transmission designs. It was followed in fairly short order by the 1950
>> Studebaker Automatic Drive, which took a somewhat different approach to
>> the same problem.
>>
>>
>>
>> https://ateupwithmotor.com/terms-technology-definitions/split-torque-lockup-converters/?cookie-state-change=1548616977986
>>
>> Correct me if I am wrong but 1949 and 1950 was waaaaaay before the CAFE
>> age (law was enacted by Congress in 1975). For some reason I always insist
>> on
>> accurate data. If this article about Studebaker and Packard transmissions
>> is inaccurate please let me know.
>>
>> While I sometimes wish my GMC had a wider spread of gear ratios, I would
>> think a lockup converter would be a benefit while cruising at light to
>> moderate loads.
>> --
>> Bob Heller
>> 1974 X-Canyonlands 26ft
>> Original 455 exc for timing chain,
>> Rockwell intake, valve covers. 145k miles.
>> Winter Springs FL
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk
> http://www.appliedgmc.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[george beckman]

> ( GRIN ) When someone says that any RPM's over 3300 RPM's. will just burn the engine up. Due to high piston speeds. That is absolutely,
> positively not true. Bob Dunahugh 78 Royale
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

I agree with Bob. I lost my governer gear on a rolling rally. We could not pull the governor because the pin had worked out, hitting the case and
locking it in. (Who knows why, because that roll pin is tight!)

Anyway, I drove about 120 miles home in low gear. I never used to run my 455 over 3200 and never even 3000 for long times. All I can say is after a
while, 4000 RPMs doesn't sound so bad.

After you fix the transmission, you think, "This is sure a nice quiet coach."
--
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George

 

[john phillips]

James,
So from about 2000 to 3000 RPM the slippage reduces but never locks up. The
more slippage in the converter the more heat is generated which does
require more fuel burn. The extra fuel burn must not be very much or we
would be seeing people talking about upgrading to a lockup converter to
save fuel.
Correct me if I am wrong but I figured my front wheels at the present tire
pressure have an effective circumference of 84 inches. 2500 engine RPM
/3.07 final drive gives a wheel RPM of 814. 814 * 84 /12 inches per foot *
60 minutes per hour / 5280 feet per mile comes out to 64.8 MPH with 0 slip.
Comes out to 25.9 miles/1000RPM.

I have felt that running in the low 2000sands would lengthen engine life as
long as the engine was not working hard.

My car rarely gets to 2500 RPM.

> Depending upon whether or not your torque converter is original or has been
> upgraded, you probably have a converter with a 2500 rpm stall speed. That
> is NOT TO SAY THAT IT "LOCKS UP" because it never really does that. There
> is always some slippage between engine speed and transmission input shaft
> speed.
> A true "lock up" converter is the same as a manual clutch (very little
> slippage).
> So, at 2100 rpm, your engine is turning faster than your transmission
> input shaft, and some heating of the transmission fluid is occurring as a
> result of that slippage. Engineers have to account for energy loss through
> moving something by applying a force (work) or by heat loss.
> Jim Hupy
>
>

>

> > > Matt
> > >
> > > > I have the original Avion VIN A26000 with a GMC Firewall VIN of
> > > > TZE064V10116 with a 455 and headers. Given that our drive wheels
> are
> > > > about 15% larger than the car version the 3.07 would be like having
> a
> > 2.60
> > > > in the Toronado towing package. Not much of a towing package. So
> > unless you
> > > > are going to do a lot of flatland 80 mph driving in a very light
> > coach a
> > > > higher final drive ratio would be in order. A 3.53 would match the
> > Toronado
> > > > towing package . Will a higher final drive ratio take some of the
> > strain
> > > > off of the transmission and the rest of the drivetrain?
> > >
> > > * My coach is a very light 23. With the stock cam, it suffered at
> 60~65.
> > > That was 21~2200 with the converter slip (it is not fully engaged at
> > those*
> > > *road speeds). *
> > > Are you implying that you need more RPMs to get the torque converter to
> > > lock up/not slip? Is there a lockup clutch in our converter?
> >
> > Yes John,
> >
> > That is exactly what I am saying and there was no lock-up version of
> > torque converter for transmissions of this era. That did not come along
> > until
> > CAFE hit the scene. (Unless you were brave enough to try to drive a
> street
> > car with a "Clutch-Flyt".
> >
> > Matt
> >
> > Quote:

> > >
> > > > I have four extra gages on my 78 Royale 403. Vacuum, Tachometer,
> > > > Transmission fluid temperature at the Ragusa finned aluminum pan,
> and
> > final
> > > > drive oil temperature. The Tachometer and Vacuum gage are mounted
> > between
> > > > the drivers side windshield and the horse collar that surrounds the
> > dash.
> > > > The oil gages are mounted where the ash tray used to be.
> > > > I often run my 403 between 3000 and 3600 rpm. With the final
> > drive
> > > > and wheel and tire combinations that I run, that is between 62 and
> 75
> > miles
> > > > per hour. The 403 is a happy camper in that rpm range.
> > > > The 455 will not be hurt a bit at those rpms either.
> > > > If I am climbing long continuous grades, I will manually
> > downshift and
> > > > run the 403 at 4200 - 4500 rpm at 10 to 12 inches of mercury (
> > throttles
> > > > 1/2 way open) for long stretches. My original engine is still
> > equipped with
> > > > a quadrajet carb and Doug Thorley Coated headers, dual mufflers and
> a
> > 2
> > > > 3/4" tail pipe. It has over 130,000 miles and burns a quart of 20
> -50
> > > > Valvoline Dino oil in about 1500 miles. Last time I checked
> > compression, it
> > > > pumped over 150 psi across the board. I can't complain about that
> > > > performance. The best modification I ever did was the 3:70 final
> drive
> > > > gearing.
> > > > Jim Hupy
> > > >
> > > > On Sat, Jan 26, 2019, 9:21 AM roy keen
> > > >> I wouldn't be without a tack and I wouldn't run a 455 at or above
> > 4000
> > > > rpm
> > > >> for any length of time especially in these western mountains with
> the
> > > > pedal
> > > >> to the metal. If you do and the motor wasn't modified for high rpm
> > you
> > > > may
> > > >> be sorry you did.3000 is a lot safer.
> > > >> --
> > > >> Roy Keen
> > > >> Minden,NV
> > > >> 76 X Glenbrook
> > > >>
> > > >> _______________________________________________
> > > >> GMCnet mailing list
> > > >> Unsubscribe or Change List Options:
> > > >> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> > > >>
> > > > _______________________________________________
> > > > GMCnet mailing list
> > > > Unsubscribe or Change List Options:
> > > > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> > > >
> > >
> > >
> > > --
> > >
> > > *John Phillips*
> > > _______________________________________________
> > > GMCnet mailing list
> > > Unsubscribe or Change List Options:
> > > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> >
> > --
> > Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> > Electronically Controlled Quiet Engine Cooling Fan
> > OE Rear Drum Brakes with Applied Control Arms
> > SE Michigan - Twixt A2 and Detroit
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--

*John Phillips*

 

[Jim Hupy]

The REAL KEY to whether or not you are doing damage to your engine at low
rpms is load / throttle opening. If you are running at 15 inches of mercury
at 1500 rpm, you are not likely to do much damage. However, if you are
running with 4 inches of mercury, you will be lugging the heck out of your
engine.
Jim Hupy
Salem, Or

> James,
> So from about 2000 to 3000 RPM the slippage reduces but never locks up. The
> more slippage in the converter the more heat is generated which does
> require more fuel burn. The extra fuel burn must not be very much or we
> would be seeing people talking about upgrading to a lockup converter to
> save fuel.
> Correct me if I am wrong but I figured my front wheels at the present tire
> pressure have an effective circumference of 84 inches. 2500 engine RPM
> /3.07 final drive gives a wheel RPM of 814. 814 * 84 /12 inches per foot *
> 60 minutes per hour / 5280 feet per mile comes out to 64.8 MPH with 0 slip.
> Comes out to 25.9 miles/1000RPM.
>
> I have felt that running in the low 2000sands would lengthen engine life as
> long as the engine was not working hard.
>
> My car rarely gets to 2500 RPM.
>

>
> > Depending upon whether or not your torque converter is original or has
> been
> > upgraded, you probably have a converter with a 2500 rpm stall speed. That
> > is NOT TO SAY THAT IT "LOCKS UP" because it never really does that. There
> > is always some slippage between engine speed and transmission input shaft
> > speed.
> > A true "lock up" converter is the same as a manual clutch (very
> little
> > slippage).
> > So, at 2100 rpm, your engine is turning faster than your
> transmission
> > input shaft, and some heating of the transmission fluid is occurring as a
> > result of that slippage. Engineers have to account for energy loss
> through
> > moving something by applying a force (work) or by heat loss.
> > Jim Hupy
> >
> >

> >

> > > > Matt
> > > >
> > > > > I have the original Avion VIN A26000 with a GMC Firewall VIN of
> > > > > TZE064V10116 with a 455 and headers. Given that our drive wheels
> > are
> > > > > about 15% larger than the car version the 3.07 would be like
> having
> > a
> > > 2.60
> > > > > in the Toronado towing package. Not much of a towing package. So
> > > unless you
> > > > > are going to do a lot of flatland 80 mph driving in a very light
> > > coach a
> > > > > higher final drive ratio would be in order. A 3.53 would match the
> > > Toronado
> > > > > towing package . Will a higher final drive ratio take some of the
> > > strain
> > > > > off of the transmission and the rest of the drivetrain?
> > > >
> > > > * My coach is a very light 23. With the stock cam, it suffered at
> > 60~65.
> > > > That was 21~2200 with the converter slip (it is not fully engaged at
> > > those*
> > > > *road speeds). *
> > > > Are you implying that you need more RPMs to get the torque converter
> to
> > > > lock up/not slip? Is there a lockup clutch in our converter?
> > >
> > > Yes John,
> > >
> > > That is exactly what I am saying and there was no lock-up version of
> > > torque converter for transmissions of this era. That did not come
> along
> > > until
> > > CAFE hit the scene. (Unless you were brave enough to try to drive a
> > street
> > > car with a "Clutch-Flyt".
> > >
> > > Matt
> > >
> > > Quote:

> > > >
> > > > > I have four extra gages on my 78 Royale 403. Vacuum, Tachometer,
> > > > > Transmission fluid temperature at the Ragusa finned aluminum pan,
> > and
> > > final
> > > > > drive oil temperature. The Tachometer and Vacuum gage are mounted
> > > between
> > > > > the drivers side windshield and the horse collar that surrounds
> the
> > > dash.
> > > > > The oil gages are mounted where the ash tray used to be.
> > > > > I often run my 403 between 3000 and 3600 rpm. With the final
> > > drive
> > > > > and wheel and tire combinations that I run, that is between 62 and
> > 75
> > > miles
> > > > > per hour. The 403 is a happy camper in that rpm range.
> > > > > The 455 will not be hurt a bit at those rpms either.
> > > > > If I am climbing long continuous grades, I will manually
> > > downshift and
> > > > > run the 403 at 4200 - 4500 rpm at 10 to 12 inches of mercury (
> > > throttles
> > > > > 1/2 way open) for long stretches. My original engine is still
> > > equipped with
> > > > > a quadrajet carb and Doug Thorley Coated headers, dual mufflers
> and
> > a
> > > 2
> > > > > 3/4" tail pipe. It has over 130,000 miles and burns a quart of 20
> > -50
> > > > > Valvoline Dino oil in about 1500 miles. Last time I checked
> > > compression, it
> > > > > pumped over 150 psi across the board. I can't complain about that
> > > > > performance. The best modification I ever did was the 3:70 final
> > drive
> > > > > gearing.
> > > > > Jim Hupy
> > > > >
> > > > > On Sat, Jan 26, 2019, 9:21 AM roy keen
> > > > >> I wouldn't be without a tack and I wouldn't run a 455 at or above
> > > 4000
> > > > > rpm
> > > > >> for any length of time especially in these western mountains with
> > the
> > > > > pedal
> > > > >> to the metal. If you do and the motor wasn't modified for high
> rpm
> > > you
> > > > > may
> > > > >> be sorry you did.3000 is a lot safer.
> > > > >> --
> > > > >> Roy Keen
> > > > >> Minden,NV
> > > > >> 76 X Glenbrook
> > > > >>
> > > > >> _______________________________________________
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> > > >
> > > >
> > > > --
> > > >
> > > > *John Phillips*
> > > > _______________________________________________
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> > >
> > >
> > > --
> > > Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> > > Electronically Controlled Quiet Engine Cooling Fan
> > > OE Rear Drum Brakes with Applied Control Arms
> > > SE Michigan - Twixt A2 and Detroit
> > >
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>
>
> --
>
> *John Phillips*
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