Hot Rod Forum banner
1 - 16 of 16 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter · #1 ·
I have a GM cast iron 4bbl Dual exhaust manifole for a straight six engine. I was wondweing if anyone knows what this would have came off of, and will it fit on my son's 250 six cyl in his pickup. I looks like it is thew same bolt pattern
any info or experiance will be appricated.
thanks:)
 

·
Administrator
Joined
·
18,633 Posts
The only 4bbl GM that I know of that came from the factory was the OHC six that came in the 1st Pontiac Firebirds. It may have came from one of those.
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #4 ·
Thanks Folks.
I will do some more checking, and check that website.
We're not quite ready to tear it down yet, so my son and I have some time.

I also wanted everyone to know , I don't have access to the computer all of the time so if I take a while to get back to you I'm not trying to be rude.
Thanks again for any and all help
 

·
Registered
Joined
·
2,384 Posts
Will it fit?

The only 4 bbl 6 cylinder intake I ever recall seeing from GM was for the Pontiac OHC engine.
It may not have been made for your engine, but it would be a hoot to see just how close it would come to fitting. It could well be that it would only take some minor mods to do it. I would get an intake gasket,( dont need a new one), and do some comparing.
 

·
Registered
Joined
·
2,384 Posts
4 bbl intake

I am curious about something. Did this intake come with a carb on it? If so, what kind and any idea what size?

If you can make it work on that 250 CID 6 pack, I would recommend a 390 CFM 4 bbl carb. This will totally enhance your mid and upper end power, and running off the soda straw primaries, will most likely give you as good or better gas mileage than you get with the one holer.
 

·
Administrator
Joined
·
18,633 Posts
poncho62 said:
The only 4bbl GM that I know of that came from the factory was the OHC six that came in the 1st Pontiac Firebirds. It may have came from one of those.
The OHC Pontiacs came with an optional Quadrajet............................

BTW...you're welcome too....I identified the manifold in the 2nd post of this thread.
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #10 · (Edited)
Hi poncho62
I appriciate it. I never suspected that Pontiac made any 4 bbl stuff for a 6. I am trying some web searches, and am planning to go down to Tulsa, to look at some of the bigger book stores for some background on it.

I have to admit I was at a loss as I had found no info about on any kind of Chevy.

Thanks:thumbup:

About the carb, I looks like a quadrajet bore, to me. I have the intake down being vatted to clean it up, right now.

we will try the gasket match and if it's close will take to down and have it surface ground to smooth it up.
Any recomendations about carb size.
 

·
Registered
Joined
·
2,384 Posts
4 bbl 6 pack

I would go with the Holley 390 CFM with vacuum secondaries. They have a model thats geared for small displacement engines.

RE: My previous post on carbs.
I am curious about something. Did this intake come with a carb on it? If so, what kind and any idea what size?

If you can make it work on that 250 CID 6 pack, I would recommend a 390 CFM 4 bbl carb. This will totally enhance your mid and upper end power, and running off the soda straw primaries, will most likely give you as good or better gas mileage than you get with the one holer.
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #12 ·
No carb was on it when I found it. It has the intake and dual exhaust mounted together just like the factory 1 bbl set ups. there are three bolts attaching the two manifolds together comming up from the bottom, right under the carb base
 

·
Registered
Joined
·
2,384 Posts
4 bbl intake

Im hoping you that with overlaying your 250 gaskets on the intake and exhaust, that they will be close enough that a person could bolt them to your 250, with little or no modifications. If the intake will work and exhaust wont, theres always the option of dropping off the exhuast and putting on aftermarket headers.
Time will tell.
 

·
Registered
Joined
·
8 Posts
Discussion Starter · #16 ·
Found out what it's fits

I finally found what engine it fits. It is for a 230 Pontiac OHC engine.

I tried matching gaskets, and found that the ports are quite a bit larger than the common 250 Chevy and GMC engines.

So I guess that I will go with an aftermarket intake and exhaust setup.

I would like to thank everyone for there input, which allowed me to identifiy this intake.

Hope everyone has a happy new year!
 
1 - 16 of 16 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top