Intake manifold search

[jack ramsey]

Getting close to driving it: My 75 Palm Beach was rebuilt by the PO in 1997 and then sat for most of the last 20 years (dry Calif Valley). It has a
Edlebrock "High rise" aluminum manifold on it and the dog house raised up at least 6 inches. Not my idea of optimal space usage in a small aluminum
and fiberglass tube. Looks like an old performer type and while the PO was impressed with the performance, I will put TBI on it and most certainly
change out the manifold to create an open space in the front of the coach.

I know the Mondello is the way to go. Has anyone machined down the huge "high rise" part of one of these edlebrock's or do I just bite the $1K bullet
and go the Mondello?

Does anything fit under the GMC floor beside the stock intake or the Mondello?

Thanks,

jack
--
Jack Ramsey
Tulare, CA
TZE165V101526
1975 Palm Beach

 

[Jim Hupy]

Stock 455 Motor home cast iron manifold with the crossover passages blocked
with Patterson or Mondello plates will work fine at the rpm's we run our
coaches. Second choice would be the Rockwell aluminum intake from Jim K.
Last would be Edelbrock or Mondello because of the lifted floor. If you are
running a 403, the Edelbrock Performer will work with a quadrajet and stock
air cleaner.
Jim Hupy
Salem, Or
78 GMC ROYALE 403

> Getting close to driving it: My 75 Palm Beach was rebuilt by the PO in
> 1997 and then sat for most of the last 20 years (dry Calif Valley). It has a
> Edlebrock "High rise" aluminum manifold on it and the dog house raised up
> at least 6 inches. Not my idea of optimal space usage in a small aluminum
> and fiberglass tube. Looks like an old performer type and while the PO was
> impressed with the performance, I will put TBI on it and most certainly
> change out the manifold to create an open space in the front of the coach.
>
> I know the Mondello is the way to go. Has anyone machined down the huge
> "high rise" part of one of these edlebrock's or do I just bite the $1K
> bullet
> and go the Mondello?
>
> Does anything fit under the GMC floor beside the stock intake or the
> Mondello?
>
> Thanks,
>
> jack
> --
> Jack Ramsey
> Tulare, CA
> TZE165V101526
> 1975 Palm Beach
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[emerystora]

Check the manifolds shown at appliedgmc.com http://appliedgmc.com/ .
You can also call Jim Kanomata at Applied GMC as he may have others that are not listed on his site.

Emery Stora
77 Kingsley
Frederick, CO

>
> Getting close to driving it: My 75 Palm Beach was rebuilt by the PO in 1997 and then sat for most of the last 20 years (dry Calif Valley). It has a
> Edlebrock "High rise" aluminum manifold on it and the dog house raised up at least 6 inches. Not my idea of optimal space usage in a small aluminum
> and fiberglass tube. Looks like an old performer type and while the PO was impressed with the performance, I will put TBI on it and most certainly
> change out the manifold to create an open space in the front of the coach.
>
> I know the Mondello is the way to go. Has anyone machined down the huge "high rise" part of one of these edlebrock's or do I just bite the $1K bullet
> and go the Mondello?
>
> Does anything fit under the GMC floor beside the stock intake or the Mondello?
>
> Thanks,
>
> jack
> --
> Jack Ramsey
> Tulare, CA
> TZE165V101526
> 1975 Palm Beach
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[powwerjon]

Jack,
You have several options to remove the elevated floor. You can use a stock
CI manifold that has been checked for cracks and installed with the exhaust
crossovers blocked. Or you can get the new aluminum unit.

http://www.appliedgmc.com/prod.itml/icOid/568

There are a number of the CI manifolds available and I have one in the shop
that would have to be check for cracks. You would just have to install the
crossover block off plates.

http://www.appliedgmc.com/prod.itml/icOid/569

http://www.appliedgmc.com/prod.itml/icOid/827

The next step is what kind of fuel system as there are very good carbs
available along with very good TBI units and a few MPFI units also.

J.R. Wright
GMC Great Laker
GMC Eastern States
GMCMHI
TZE Zone Restorations
78 Buskirk Custom 30' Stretch
75 Avion (Under going Frame up Restoration)

> Getting close to driving it: My 75 Palm Beach was rebuilt by the PO in
> 1997 and then sat for most of the last 20 years (dry Calif Valley). It has a
> Edlebrock "High rise" aluminum manifold on it and the dog house raised up
> at least 6 inches. Not my idea of optimal space usage in a small aluminum
> and fiberglass tube. Looks like an old performer type and while the PO was
> impressed with the performance, I will put TBI on it and most certainly
> change out the manifold to create an open space in the front of the coach.
>
> I know the Mondello is the way to go. Has anyone machined down the huge
> "high rise" part of one of these edlebrock's or do I just bite the $1K
> bullet
> and go the Mondello?
>
> Does anything fit under the GMC floor beside the stock intake or the
> Mondello?
>
> Thanks,
>
> jack
> --
> Jack Ramsey
> Tulare, CA
> TZE165V101526
> 1975 Palm Beach
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[powwerjon]

Jack,
You have several options to remove the elevated floor. You can use a stock CI manifold that has been checked for cracks and installed with the exhaust crossovers blocked. Or you can get the new aluminum unit.

http://www.appliedgmc.com/prod.itml/icOid/568

There are a number of the CI manifolds available and I have one in the shop that would have to be check for cracks. You would just have to install the crossover block off plates.

http://www.appliedgmc.com/prod.itml/icOid/569

http://www.appliedgmc.com/prod.itml/icOid/827

The next step is what kind of fuel system as there are very good carbs available along with very good TBI units and a few MPFI units also.

J.R. Wright
GMC GreatLakerTech Editor
78 Buskirk 30' Stretch
75 Avion Under Reconstruction
Michigan

>
> Check the manifolds shown at appliedgmc.com http://appliedgmc.com/ .
> You can also call Jim Kanomata at Applied GMC as he may have others that are not listed on his site.
>
> Emery Stora
> 77 Kingsley
> Frederick, CO
>

>>
>> Getting close to driving it: My 75 Palm Beach was rebuilt by the PO in 1997 and then sat for most of the last 20 years (dry Calif Valley). It has a
>> Edelbrock "High rise" aluminum manifold on it and the dog house raised up at least 6 inches. Not my idea of optimal space usage in a small aluminum
>> and fiberglass tube. Looks like an old performer type and while the PO was impressed with the performance, I will put TBI on it and most certainly
>> change out the manifold to create an open space in the front of the coach.
>>
>> I know the Mondello is the way to go. Has anyone machined down the huge "high rise" part of one of these edelbrock's or do I just bite the $1K bullet
>> and go the Mondello?
>>
>> Does anything fit under the GMC floor beside the stock intake or the Mondello?
>>
>> Thanks,
>>
>> jack
>> --
>> Jack Ramsey
>> Tulare, CA
>> TZE165V101526
>> 1975 Palm Beach
>>
>> _______________________________________________
>> 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

 

[jim kanomata1]

Our AL. Intake has the A/C bracket hole redone to allow the bracket to fit
properly.
Otherwise you'll need to redo it on your own.

> Jack,
> You have several options to remove the elevated floor. You can use a
> stock CI manifold that has been checked for cracks and installed with the
> exhaust crossovers blocked. Or you can get the new aluminum unit.
>
> http://www.appliedgmc.com/prod.itml/icOid/568
>
> There are a number of the CI manifolds available and I have one in the
> shop that would have to be check for cracks. You would just have to
> install the crossover block off plates.
>
> http://www.appliedgmc.com/prod.itml/icOid/569
>
> http://www.appliedgmc.com/prod.itml/icOid/827
>
> The next step is what kind of fuel system as there are very good carbs
> available along with very good TBI units and a few MPFI units also.
>
> J.R. Wright
> GMC GreatLakerTech Editor
> 78 Buskirk 30' Stretch
> 75 Avion Under Reconstruction
> Michigan
>

> >
> > Check the manifolds shown at appliedgmc.com http://appliedgmc.com/ .
> > You can also call Jim Kanomata at Applied GMC as he may have others that
> are not listed on his site.
> >
> > Emery Stora
> > 77 Kingsley
> > Frederick, CO
> >

> >>
> >> Getting close to driving it: My 75 Palm Beach was rebuilt by the PO in
> 1997 and then sat for most of the last 20 years (dry Calif Valley). It has a
> >> Edelbrock "High rise" aluminum manifold on it and the dog house raised
> up at least 6 inches. Not my idea of optimal space usage in a small aluminum
> >> and fiberglass tube. Looks like an old performer type and while the PO
> was impressed with the performance, I will put TBI on it and most certainly
> >> change out the manifold to create an open space in the front of the
> coach.
> >>
> >> I know the Mondello is the way to go. Has anyone machined down the huge
> "high rise" part of one of these edelbrock's or do I just bite the $1K
> bullet
> >> and go the Mondello?
> >>
> >> Does anything fit under the GMC floor beside the stock intake or the
> Mondello?
> >>
> >> Thanks,
> >>
> >> jack
> >> --
> >> Jack Ramsey
> >> Tulare, CA
> >> TZE165V101526
> >> 1975 Palm Beach
> >>
> >> _______________________________________________
> >> 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
>
>
> _______________________________________________
> 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

 

[chris tyler]

I know the Mondello is the way to go. Has anyone machined down the huge "high rise" part of one of these edlebrock's or do I just bite the $1K bullet
and go the Mondello?


I picked a performer up at a swap meet a while back and ended up not using it

Ttalked to Edelbrock about milling it and they said maximum of 1/2" inch as I recall which wouldnt gain much or be worth the removal. The runners are
much higher, it isn just the plenum or mounting flange

Discussing the appplication they saidthey had no data below 2500 rpm but didnt feel it would lose anylow end torque under 3500 and would be about
10-12 better at 4500.

I wouldnt ming the hump myself as I use an f150 console there anyway but it didnt seem worth the effort to change it out.
--
76 Glenbrook

 

[Ken H.]

Anyone even remotely considering using the Edelbrock Performer manifold on
a 455 should be aware of a BIG potential problem: To preserve the
warranty, Edelbrock requires the use of the provided cast iron plugs in the
exhaust ports on the heads (like these:
https://www.summitracing.com/int/parts/edl-2733/overview/?retaillocation=int
).

They WILL damage cylinder heads. I got lucky and removed them before they
wore into the water jacket; others have not been so lucky:
http://www.gmcmhphotos.com/photos/g3057-cylinder-head-damage-from-exhaust-crossover-plugs.html

Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, Troy-Bilt APU, etc., etc., etc.
www.gmcwipersetc.com

On Thu, Mar 15, 2018 at 9:28 AM, Chris Tyler
wrote:

>
>
> I know the Mondello is the way to go. Has anyone machined down the huge
> "high rise" part of one of these edlebrock's or do I just bite the $1K
> bullet
> and go the Mondello?
>
>
> I picked a performer up at a swap meet a while back and ended up not using
> it
>
> Ttalked to Edelbrock about milling it and they said maximum of 1/2" inch
> as I recall which wouldnt gain much or be worth the removal. The runners are
> much higher, it isn just the plenum or mounting flange
>
> Discussing the appplication they saidthey had no data below 2500 rpm but
> didnt feel it would lose anylow end torque under 3500 and would be about
> 10-12 better at 4500.
>
> I wouldnt ming the hump myself as I use an f150 console there anyway but
> it didnt seem worth the effort to change it out.
> --
> 76 Glenbrook
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

 

[jack ramsey]

I see in the photo site John Heslinga who I think has a 74 (so should be a 455) installed a Performer intake manifold and also was using a standard
engine cover.
John is that accurate or did you do an engine change?

Thanks,

Jack (grasping at straws)

--
Jack Ramsey
Tulare, CA
TZE165V101526
1975 Palm Beach

 

[robert mueller]

Jack,

I perused John's photo albums and could not find a photo of the "cockpit" showing the flat standard OEM engine cover. As far as I
know the Performer won't fit unless you install a dog house (raised) cover.

Below you will find an email I sent in back in 2015:

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Robert Mueller
Sent: Monday, March 30, 2015 4:40 PM
To: gmclist
Subject: [GMCnet] 455 Intake Manifolds

G'day,

Before I returned to Sydney I took the three intake manifolds for a 455 GMC I have in Houston took some measurements I thought might
be helpful:

I turned them over on my workbench and sat them on the carb mounting surface then measured the distance from the workbench to the
front lifter valley sealing surface and the rear lifter valley sealing surface.

OEM Manifold

Front: 3.55 inches
Rear: 3.77 inches

Edelbrock Performer

Front: 4.50 inches
Rear: 5.60 inches

Edelbrock Performer that has had the carb mounting surface milled down reducing the height.

Front: 3.76 inches
Rear: 4.08 inches

The depth of the plenum under the carb mounting surface is about the same as the OEM manifold.

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808


-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Jack Ramsey
Sent: Friday, April 13, 2018 9:10 PM
To: gmclist
Subject: [GMCnet] Intake manifold search

I see in the photo site John Heslinga who I think has a 74 (so should be a 455) installed a Performer intake manifold and also was
using a standard engine cover.

John is that accurate or did you do an engine change?

Thanks,

Jack (grasping at straws)

--
Jack Ramsey
Tulare, CA
TZE165V101526
1975 Palm Beach

_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

 

[jack ramsey]

Thanks Rob,
Looks like John's pic I saw was was pre-purchase. (link below)

I have resolved the issue and ordered a complete Atomic MSD fuel Injection system, and used intake manifold with proper gaskets and block-off, from
Nick at Applied 20 min ago.
The measurements tell me there is hope and I will play with my existing Performer IF and when I have the spare time. Right now i just want it rolling
and do some short close to home runs to evaluate the remaining semi-touched systems before a longer late summer planned trip to the Midwest.

Thanks again,

Jack

http://www.gmcmhphotos.com/photos/purchasing-my-74-canyonlands/p42042-additional-photos-from-subsequent-e-mail-communication-pre-purchase-74-ca.html

--
Jack Ramsey
Tulare, CA
TZE165V101526
1975 Palm Beach

 

[JHeslinga]

Jack: Sorry that I have not responded earlier. I do not read the forum as much as I once did. There is no negative reason for this other than I am
busy doing other things in my life and there is only so much time I can spend on the computer. However I do review the entrys regularly simply to see
whats going on. I do have a Edelbrock performer manifold on my 1974 455. The Carburetor mount as not been milled down. Yes the engine
cover has been modified to accommodate the increased height of the engine. I created a doghouse 3 1/2 inches simply large enough to go around the
Air Cleaner to make up for the needed space. This gives us places to put our foot when climbing into the seats.

Using a performer manifold results in a number of modifications being required, so please consider this if you choose to do a change over. The
Snorkel of the air cleaner will no longer fit under the floor and will need some kind of modifications. The Cruise control vacuum servo is also no
longer aligned properly to the throttle lever meaning the the linkage needs modifying. I also found that I needed to make a couple modifications to
a web on the manifold to allow the distributor Vacuum advance pot to rotate further into the manifold Giving the wires a better line to the plugs.
I created an air box for the snorkel and use a modified Intake hose from a more modern intake system to go under the floor. The Hot air valve now
operates under the floor as well. Here are some photos giving you an idea what I did. I have more if needed but you get the idea.

engine Cover Modification needed.
http://www.gmcmhphotos.com/photos/discussion-photos/p64775-performer-manifold-engine-cover-modifications.html

Manifold Web Modification
http://www.gmcmhphotos.com/photos/discussion-photos/p64774-performer-manifold-web-modification.html

Throttle linkage modification
http://www.gmcmhphotos.com/photos/discussion-photos/p64773-performer-manifold-throttle-linkage-modification.html

Air Cleaner Modification.
http://www.gmcmhphotos.com/photos/discussion-photos/p64772-performer-manifold-air-cleaner-mod.html

--
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta

 

[jack ramsey]

Thanks John,

I already have a performer, and while it is not a REAL problem, the exaggerated doghouse is.

http://www.gmcmhphotos.com/photos/atomic-tbi-fuel-injection/p64781-start-with-performer-and-ridiculous-doghouse.html

It (carb and air cleaner) does not stick up that far

http://www.gmcmhphotos.com/photos/atomic-tbi-fuel-injection/p64783-mess-under-the-doghouse.html

http://www.gmcmhphotos.com/photos/atomic-tbi-fuel-injection/p64785-start-with-performer-and-ridiculous-doghouse.html

I have a used Torker coming, and since it all has to come out to block off the exhaust warming, will evaluate just how far either of them can be
shaved down and see how the air cleaner either fits, snorkels, and minimize this senseless 9 inch intrusion into cab space. Looks like 5 inches would
be more than enough with just stock equipment and the performer.
--
Jack Ramsey
Tulare, CA
TZE165V101526
1975 Palm Beach

 

[david h. jarvis]

> Jack,
>
> I perused John's photo albums and could not find a photo of the "cockpit" showing the flat standard OEM engine cover. As far as I
> know the Performer won't fit unless you install a dog house (raised) cover.
>
> Below you will find an email I sent in back in 2015:
>
> -----Original Message-----
> From: Gmclist [mailto:gmclist-bounces] On Behalf Of Robert Mueller
> Sent: Monday, March 30, 2015 4:40 PM
> To: gmclist
> Subject: [GMCnet] 455 Intake Manifolds
>
> G'day,
>
> Before I returned to Sydney I took the three intake manifolds for a 455 GMC I have in Houston took some measurements I thought might
> be helpful:
>
> I turned them over on my workbench and sat them on the carb mounting surface then measured the distance from the workbench to the
> front lifter valley sealing surface and the rear lifter valley sealing surface.
>
> OEM Manifold
>
> Front: 3.55 inches
> Rear: 3.77 inches
>
> Edelbrock Performer
>
> Front: 4.50 inches
> Rear: 5.60 inches
>
> Edelbrock Performer that has had the carb mounting surface milled down reducing the height.
>
> Front: 3.76 inches
> Rear: 4.08 inches
>
> The depth of the plenum under the carb mounting surface is about the same as the OEM manifold.
>
> Regards,
> Rob M.
>
> Hello Rob;
> Looking at these before and after numbers, it looks like there was .74 of an inch removed from the front of the carb
> mounting surface, but 1.52 from the rear.
> Is this correct?
> Would the carb be sitting at an angle?
> Thank you for any information.
> Dave J.

 

[JHeslinga]

Jack.
Further to you situation. I agree that the doghouse approach is not the most ideal. I found that I only needed 3 inches intrusion and I gave it a
bit more. The height in my case was not a real problem and in fact Ive come to enjoy the height as I drive down the road to put things on. Way easier
to reach!!! It is a perfect extension to the drivers table that is there. The real problem I had was that I did not want to really climb onto the
doghouse to get into our seats. By making sure there was enough foot space beside the doghouse, It is much easier to get into our seats. I placed a
floor mat strip on the carpet to ensure I don't get the carpet so dirty, You can see that space more clearly with the mat there.

http://www.gmcmhphotos.com/photos/discussion-photos/p64787-performer-manifold-doghouse.html

That space was larger when I had an aftermarket Air cleaner that I originally used. I thought that air cleaner would be a cooler, sexier, and most
effective. I really hated it. It was far too noisy for me. The constant hiss from from the part throttle operation and the Horrendous ROAR when the
secondaries began to open. That might be OK for a young guy but we could hardly talk!! The stock air cleaner is actually designed as a noise
limiter and it became a desirable thing. After adapting it I was a lot more happy. The doghouse needed another slight adjustment to its footprint
but the end results were better. Of course, noise limiting strategies in the entire cab area also became important to me, hence the underlay and
carpet!! The extra space I gave the cover and doghouse will also allow me to install commercial noise limiting strategies on the underside of the
hood. ( However: I'm pretty happy with the way it is at the moment.)

http://www.gmcmhphotos.com/photos/discussion-photos/p64788-performer-manifold-air-cleaner.html
--
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta

 

[JHeslinga]

One last thing,

One other thing I found with the performer manifold is that the angle of the carburetor mouthing surface is designed for regular cars in which the
engine is mounted at a much larger front to rear angle than the Toronado and the Coach. The coach engine is much closer to level when mounted in the
engine cradle. The angle of the carb mount surface is designed to keep the carb level in those other cars. In my opinion the carburetor has too much
forward rake in the coach. I spoke to a machinist (I don't have a mill) if he could mill some height and angle out of the high rise of the
manifold. He did not want to try because he was afraid that there would be too much vibration and cause too much chatter and poor finish. I not
sure I agree but I did not bother looking for another machinist. I regret not taking it further, I'm sure it would not be a problem, and if anyone
has had it done I would like to know how things worked out. If I need to take out the manifold again, I will take that further. Please consider
having yours done if you intend to use it again.
Best Regards.

--
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta

 

[Ken H.]

My coach came with a Performer when I bought it in '98. It stayed on there
for maybe 2 years. After I removed it, I was frequently asked "did you
notice any power loss"? My honest answer was always, "Not below 4000
rpm". Are Y'All finding differently, to justify all the doghouse
detriments?

Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI & EBL,
Manny Brakes & 1-Ton, Troy-Bilt APU, etc., etc., etc.
www.gmcwipersetc.com

> Thanks John,
>
> I already have a performer, and while it is not a REAL problem, the
> exaggerated doghouse is.
> ​...
>

 

[robert mueller]

David,

I did not do the machining, I got the Performers from Jim Roundtree up in San Antonio. Unfortunately Jim has passed away so I can't
get any info about them from him.

Please note:

"I turned them over on my workbench and sat them on the carb mounting surface then measured the distance from the workbench to the
front lifter valley sealing surface and the rear lifter valley sealing surface."

Unfortunately this does not show how much was milled off the carb mounting surface and I don't know how I could provide that
measurement without installing the Performer on an engine installed in a GMC and placing a straight edge side to side on the cockpit
floor and measuring from the straight edge down to the front of the carb mounting surface and the back of the carb mounting surface.

I may be R&Ring the intake manifold on Double Trouble and if I do I'll take the measurements.

Regards,
Rob M.
The Pedantic Mechanic
Sydney, Australia
AUS '75 Avion - The Blue Streak TZE365V100428
USA '75 Avion - Double Trouble TZE365V100426
USA '77 Kingsley - TZE 267V100808


-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of David H. Jarvis
Sent: Monday, April 23, 2018 11:29 PM
To: gmclist
Subject: Re: [GMCnet] Intake manifold search

Hello Rob;

Looking at these before and after numbers, it looks like there was .74 of an inch removed from the front of the carb mounting
surface, but 1.52 from the rear.

Is this correct?

Would the carb be sitting at an angle?

Thank you for any information.

Dave J.


> -----Original Message-----
> From: Gmclist [mailto:gmclist-bounces] On Behalf Of Robert Mueller
> Sent: Monday, March 30, 2015 4:40 PM
> To: gmclist
> Subject: [GMCnet] 455 Intake Manifolds
>
> G'day,
>
> Before I returned to Sydney I took the three intake manifolds for a 455 GMC I have in Houston took some measurements I thought
might be helpful:
>
> I turned them over on my workbench and sat them on the carb mounting surface then measured the distance from the workbench to the
front lifter valley sealing surface and the rear lifter valley sealing surface.
>
> OEM Manifold
>
> Front: 3.55 inches
> Rear: 3.77 inches
>
> Edelbrock Performer
>
> Front: 4.50 inches
> Rear: 5.60 inches
>
> Edelbrock Performer that has had the carb mounting surface milled down reducing the height.
>
> Front: 3.76 inches
> Rear: 4.08 inches
>
> The depth of the plenum under the carb mounting surface is about the same as the OEM manifold.
>
> Regards,
> Rob M.
>

 

[JHeslinga]

Ken: regarding your comment: "did you
notice any power loss"? My honest answer was always, "Not below 4000
rpm". Are Y'All finding differently, to justify all the doghouse
detriments?"

I used the performer manifold because i had a minor crack in my stock manifold snd i had the performer. The changeoverwas for finance more than any
other reason.
I hoped there might be some improvement as a by-product. ( I admit, the Sexy look was OK Too) But honestly, I cannot say that I "feel" any
performance improvement. I don't rev over 4000 RPM for any more than a few seconds at a time. That being said: it takes a lot of difference to feel
any difference in power through the seat of your pants. I would not stand up and recommend changing over as a significant improvement in
performance. It is a lot of work to do it right with little seat of your pants, measureable return.

Regards
--
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta

 

[JHeslinga]

One thing that I always thought about milling the carb mounting surface to a different angle is a problem it could cause to the carb mounting bolt
holes and considering the possible consequences. Currently they will be properly drilled, perpendicular to the carb mounting surface. A change in
surface angle will mean the holes would no longer be perpendicular but be at a new angle reflecting the angle change of the mounting surface. This
must certainly create a problem bolting the carb to the manifold without setting up stresses on the carb. (Or the longer bolts may not even start
properly)

Another step in the process may be filling the bolt holes with aluminium threaded rod and redrilling and threading them at the proper perpendicular
orientation.

Like I said its a lot of work to do it properly.
--
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta