GMC STOCK CAST IRON INTAKE

I can't equate the combined gain of weight savings and any possible power or fuel economy increase with the $1K+ price for parts plus labor, so I
would have to do it for fun. In that case, modding the interior would already have to be in the plans. Then just build the clear engine box and don't
walk on it.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.
 
I am no expert, and maybe someone can put the engineering thoughts to the exact number. But my opinion there is very little to gain in performance
by switching to any different manifolds. we run lower rpm, so really do not need huge flow. I am sure there is some improvement, but not sure it
is worth anything. The reason to change manifolds is all based on other factors.

my observations, is that many of the original manifolds are coming up cracked. So the idea of new manifold is appealing. People install block off
plates, and also fill the crossover, but if you can buy a new manifold, why not? last year I seen a stack of 7 cracked manifolds, and at that point
the GMC'r decided to order up the aluminum one rather then keep trying to see if manifold #8 or 9 was any good.

I see many edlebrock performer manifolds installed. I have also seen people machining the carb surface to get it more level and also allow for a
little more clearance.

if you want to stick with the stock air cleaner, clearance is an issue. The stock manifold and the aluminum one that seems to be now sourced through
mondello, keep that profile so you have more clearance and should not need to raise the hatch of a 455 engine coach. Even with my EFI, clearance
is very tight to get the remote air cleaner to fit. just having a little thinner adaptor plate made a difference.

--
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
 
We supply the AL Intake manifold that is custom machined to fit the
Motorhome a

On Sun, Mar 15, 2020 at 6:51 PM Jon Roche via Gmclist <

> I am no expert, and maybe someone can put the engineering thoughts to the
> exact number. But my opinion there is very little to gain in performance
> by switching to any different manifolds. we run lower rpm, so really do
> not need huge flow. I am sure there is some improvement, but not sure it
> is worth anything. The reason to change manifolds is all based on other
> factors.
>
>
> my observations, is that many of the original manifolds are coming up
> cracked. So the idea of new manifold is appealing. People install block
> off
> plates, and also fill the crossover, but if you can buy a new manifold,
> why not? last year I seen a stack of 7 cracked manifolds, and at that point
> the GMC'r decided to order up the aluminum one rather then keep trying to
> see if manifold #8 or 9 was any good.
>
> I see many edlebrock performer manifolds installed. I have also seen
> people machining the carb surface to get it more level and also allow for a
> little more clearance.
>
> if you want to stick with the stock air cleaner, clearance is an issue.
> The stock manifold and the aluminum one that seems to be now sourced through
> mondello, keep that profile so you have more clearance and should not need
> to raise the hatch of a 455 engine coach. Even with my EFI, clearance
> is very tight to get the remote air cleaner to fit. just having a little
> thinner adaptor plate made a difference.
>
>
> --
> Jon Roche
> 75 palm beach
> EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
> St. Cloud, MN
> http://lqqkatjon.blogspot.com/
>
> _______________________________________________
> 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.gmcrvparts.com
1-800-752-7502
 
> We supply the AL Intake manifold that is custom machined to fit the
> Motorhome a
>
> On Sun, Mar 15, 2020 at 6:51 PM Jon Roche via Gmclist <

>
>> I am no expert, and maybe someone can put the engineering thoughts to
>> the exact number. But my opinion there is very little to gain in
>> performance
>> by switching to any different manifolds. we run lower rpm, so really do
>> not need huge flow. I am sure there is some improvement, but not sure it
>> is worth anything. The reason to change manifolds is all based on other
>> factors.
>>
>>
>> my observations, is that many of the original manifolds are coming up
>> cracked. So the idea of new manifold is appealing. People install block
>> off
>> plates, and also fill the crossover, but if you can buy a new manifold,
>> why not? last year I seen a stack of 7 cracked manifolds, and at that point
>> the GMC'r decided to order up the aluminum one rather then keep trying to
>> see if manifold #8 or 9 was any good.
>>
>> I see many edlebrock performer manifolds installed. I have also seen
>> people machining the carb surface to get it more level and also allow for a
>> little more clearance.
>>
>> if you want to stick with the stock air cleaner, clearance is an issue.
>> The stock manifold and the aluminum one that seems to be now sourced through
>> mondello, keep that profile so you have more clearance and should not
>> need to raise the hatch of a 455 engine coach. Even with my EFI,
>> clearance
>> is very tight to get the remote air cleaner to fit. just having a little
>> thinner adaptor plate made a difference.
>>
>>
>> --
>> Jon Roche
>> 75 palm beach
>> EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
>> St. Cloud, MN
>> http://lqqkatjon.blogspot.com/
>>
>> _______________________________________________
>> 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.gmcrvparts.com
> 1-800-752-7502
>


--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502
 
The height is same as stock and the exhaust is blocked.

The unit fits wery well as compared to the older
models.
Go to our web site as see.

>
>
> On Sun, Mar 15, 2020 at 9:47 PM Jim Kanomata

>
>> We supply the AL Intake manifold that is custom machined to fit the
>> Motorhome a
>>
>> On Sun, Mar 15, 2020 at 6:51 PM Jon Roche via Gmclist <

>>
>>> I am no expert, and maybe someone can put the engineering thoughts to
>>> the exact number. But my opinion there is very little to gain in
>>> performance
>>> by switching to any different manifolds. we run lower rpm, so really
>>> do not need huge flow. I am sure there is some improvement, but not sure
>>> it
>>> is worth anything. The reason to change manifolds is all based on other
>>> factors.
>>>
>>>
>>> my observations, is that many of the original manifolds are coming up
>>> cracked. So the idea of new manifold is appealing. People install block
>>> off
>>> plates, and also fill the crossover, but if you can buy a new manifold,
>>> why not? last year I seen a stack of 7 cracked manifolds, and at that point
>>> the GMC'r decided to order up the aluminum one rather then keep trying
>>> to see if manifold #8 or 9 was any good.
>>>
>>> I see many edlebrock performer manifolds installed. I have also seen
>>> people machining the carb surface to get it more level and also allow for a
>>> little more clearance.
>>>
>>> if you want to stick with the stock air cleaner, clearance is an
>>> issue. The stock manifold and the aluminum one that seems to be now
>>> sourced through
>>> mondello, keep that profile so you have more clearance and should not
>>> need to raise the hatch of a 455 engine coach. Even with my EFI,
>>> clearance
>>> is very tight to get the remote air cleaner to fit. just having a
>>> little thinner adaptor plate made a difference.
>>>
>>>
>>> --
>>> Jon Roche
>>> 75 palm beach
>>> EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
>>> St. Cloud, MN
>>> http://lqqkatjon.blogspot.com/
>>>
>>> _______________________________________________
>>> 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.gmcrvparts.com
>> 1-800-752-7502
>>
>
>
> --
> Jim Kanomata
> Applied/GMC, Newark,CA
> jimk
> http://www.gmcrvparts.com
> 1-800-752-7502
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502
 
At the speed the engine turns in the coach - even with a short final drive ratio, you aren't going to gain much in performance changing intakes -
there can be a weight savings of (someone said) 40 pounds over the stock iron one. To me, it ain't worth it. Swap if the original is cracked beyond
repair or use.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
 
Since 99% of driving is on the primary barrels of the Qjet, I would think a "high flow" manifold would reduce runner velocity and thereby reduce
cylinder fill. Thereby reduce torque in the real world use scenario.
--
John Lebetski
Woodstock, IL
77 Eleganza II
 
There is a reason that motorcycle engines, (high output ones, not modified
tractor engines like V-twins) use very short intake runners and a small
throated carb or fuel injector for each cylinder. It is because they
operate at amazing cfm compared to automotive applications. Large
bore/ultra short stroke by intentional design, they operate at unheard of
rpm's relative to automotive applications.
So, we have an Olds Toronado, and a Cadillac Eldorado. Front wheel
drive takes up all the under hood space that we normally use to lower the
engine in the compartment. Then, we can raise the plenums and achieve
better airflow through the intake passages.
I personally think that, given the low hood restraints, the drop
center intake does an adequate job of performing the task laid out for it.
High torque output at a very low rpm is a hard bugger to come by. Yet, that
cast iron behemoth does that job quite well. But, it cannot serve two
masters. You trade off high rpm performance for low end torque. In a
motorhome applications, that is EXACTLY what you want. Build your engine
around that specification, and you won't be sorry.
Jim Hupy
Salem, Oregon

On Mon, Mar 16, 2020, 6:59 AM John R. Lebetski via Gmclist <

> Since 99% of driving is on the primary barrels of the Qjet, I would think
> a "high flow" manifold would reduce runner velocity and thereby reduce
> cylinder fill. Thereby reduce torque in the real world use scenario.
> --
> John Lebetski
> Woodstock, IL
> 77 Eleganza II
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Jim K from Applied chimed in here just after midnight.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.
 
And 2 other threads right after that. Midnight computing... :lol:
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.
 
Would be nice if someone made a cochlea type intake sunk into the intake valley like on late model V8s, and the corresponding valley pan to close that
off and allow airflow under the intake. Long runners give even more torque at lower rpm. Really don't need to spin all those long rods and stuff past
4K in the GMC.
Must be a CAD program for 3D printers that would allow matching runners of an existing manifold and virtually any head ports. Don't have computer
powerful enough for that yet. Wouldn't know how to use program if I did.
A recent retail development has maybe solved blocking off the exhaust cross ports using 3D printed metal on that valley pan. Haven't checked to
see if there are already valley pans available for the OLDS, I'm sure there were in the past getting used mostly on drag boats and other toys... 8)
The new intakes are made of plastic, wonder if they will last through 47 years of USE? A lot of the plastics made lately are degrading
prematurely...planned obsolescence? Enviro-Engineering? Shoddy materials? Seen a lot of all three in the the past 8 years.
--
Terry Kelpien

ASE Master Technician

73 Glacier 260

Smithfield, Va.
 
Great idea but someone need to come up with few thousand that will take
several years to pay back.

On Mon, Mar 16, 2020 at 2:13 PM Terry via Gmclist
wrote:

> Would be nice if someone made a cochlea type intake sunk into the intake
> valley like on late model V8s, and the corresponding valley pan to close
> that
> off and allow airflow under the intake. Long runners give even more torque
> at lower rpm. Really don't need to spin all those long rods and stuff past
> 4K in the GMC.
> Must be a CAD program for 3D printers that would allow matching
> runners of an existing manifold and virtually any head ports. Don't have
> computer
> powerful enough for that yet. Wouldn't know how to use program if I did.
> A recent retail development has maybe solved blocking off the exhaust
> cross ports using 3D printed metal on that valley pan. Haven't checked to
> see if there are already valley pans available for the OLDS, I'm sure
> there were in the past getting used mostly on drag boats and other toys...
> 8)
> The new intakes are made of plastic, wonder if they will last through
> 47 years of USE? A lot of the plastics made lately are degrading
> prematurely...planned obsolescence? Enviro-Engineering? Shoddy materials?
> Seen a lot of all three in the the past 8 years.
> --
> Terry Kelpien
>
> ASE Master Technician
>
> 73 Glacier 260
>
> Smithfield, Va.
>
>
> _______________________________________________
> 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.gmcrvparts.com
1-800-752-7502
 
Same question. I have an Eldelbrock 3711 I never installed on my 403.

Len and Pat Novak
1978 GMC Kingsley
The Beast II with dash lights that work and labels you can see!
Fallbrook, CA new email: B52Rule
http://www.gmcmhphotos.com/photos/showgallery.php?cat=4375

www.bdub.net/novak/

-----Original Message-----
From: Gmclist [mailto:gmclist-bounces] On Behalf Of Shawn
Bennear via Gmclist
Sent: Monday, March 16, 2020 3:32 PM
To: gmclist
Cc: Shawn Bennear
Subject: Re: [GMCnet] GMC STOCK CAST IRON INTAKE

Would a Edelbrock manifold work OK on my 403 with TBI in the near future,
and still allow the hatch to close?
--
http://www.gmcmotorhomeworld.com

1977 Palm Beach, 403 V8 w headers.

_______________________________________________
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Unsubscribe or Change List Options:
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--
This email has been checked for viruses by AVG.
https://www.avg.com
 
I've had an Edelbrock on the 77 403 for about 10 years. It fits well other than i think the AC support bracket for the A3 doesn't fit. That doesn't
bother me though. I still intend to replace the old AC pump with a newer Sanden.

Don't use the edelbrock version of the crossover plugs. They don't fit the olds engine.
--
Jerrod Winter
1977 Palm Beach
Green Jelly Bean
Twin Cities, Minnesota
 
Anyone considering using an Edelbrock intake manifold should pay close
attention to Jerrod's comment about the crossover plugs -- They do not work
-- AS INTENDED. They DO work to destroy cylinder heads -- see my
experience:
http://www.gmcmhphotos.com/photos/g3057-cylinder-head-damage-from-exhaust-crossover-plugs.html

I know of at least one case in which those plugs wore into the water
jacket, eventually causing a hydraulically locked and destroyed engine.
DON'T use loose medal blocks in the exhaust ports!!! (Even tho' Edelbrock
requires them for their warranty, last I saw.)

Ken H

On Tue, Mar 17, 2020 at 1:10 PM jerrod winter via Gmclist <

> I've had an Edelbrock on the 77 403 for about 10 years. It fits well
> other than i think the AC support bracket for the A3 doesn't fit. That
> doesn't
> bother me though. I still intend to replace the old AC pump with a newer
> Sanden.
>
> Don't use the edelbrock version of the crossover plugs. They don't fit
> the olds engine.
> --
> Jerrod Winter
> 1977 Palm Beach
> Green Jelly Bean
> Twin Cities, Minnesota
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
> Would a Edelbrock manifold work OK on my 403 with TBI in the near future, and still allow the hatch to close?

Sir, the 403 is a small block Olds engine and will share the later OEM aluminum 307 Olds motor intake with efi. also will use the electronic
distributor.
--
C. Boyd
76 Crestmont
East Tennessee
 
The 403 also uses the MPFI intake off of the late 70s Seville that had a 350v8
--
Jerrod Winter
1977 Palm Beach
Green Jelly Bean
Twin Cities, Minnesota
 
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