Modified Intake manifold

Ol' Ron

Well-known member
This is an early intake manifold modified for a 2GC carb
 

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That was part of a bracket used to hold in the foam core for the intake runners. I converted to open plenum similar to the 32 intake only much larger.
 
I'm confused. The first picture looks like my 221 manifold fitted with a 97. It won't fit the bolt pattern of my 55 2bbl rochester. What is the purpose of the foam in the second picture? Is it polyurethane canned spray from Home Depot?

Jack E/NJ
 
The spacing on a 94 (between the two studs) is "close" to that of a 2g's base, but an adapter is needed. I used this one. I'm sure Ron used something similar.
 

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No, I made this intake back in the 60's as an experiment. The ruled at the track were you could use any carb that bolted to the intake, By filing the holes in the Rochester to match the intake then drilling a second hole through the pS supp port after filling it with JB weld, everything bolted up fine and ran great. Unfortunately it didn't idle well. I wouldn't recommend it for the street. And yes it was the small 2GC. I understand they come in three sizes.
 
As far as I know the 2G series came in only 2 base sizes, big and small. Chevy used the small base from 55 to the early 70's. The large base was used on Buick, Olds,and Pontiac, from the late 60's, and by the early 70's all GM vehicles used the large base version until the mid 80's.
 
Ross >>>The spacing on a 94 (between the two studs) is "close" to that of a 2g's base, but an adapter is needed. I used this one. I'm sure Ron used something similar.>>>

Of course, an adapter. I used a homemade block of oak with hand-filed tapered ports, heavily varnished. But it didn't seem any better than the 97 and looked funny. So off it came.

Jack E/NJ

PS: Still wanna know what that foam was all about?
 
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PS: Still wanna know what that foam was all about?

I'm thinking the runners were milled out, then the foam or glass put in to isolate from the valley...making it an open plenum (as Ron mentioned)...just my guess, but I assume it's all "open" above the foam and to each intake port?

Let's make him rip it all apart and show us:)
 
I think the foam was formed to the shape of the runner void. Then the walls were built up with fibreglass and /or resin and the cores then melted out, maybe by pouring gas into it. The foam was only used in the making of it, not in the finished article.

Mart.
 
Mart has it. The foam was just a core. Once the rosin hardened I pored gas in to melt the foam. This was hi tech for the 60's
Back in the old days the car mags would have allot of information on how to do it. Mostly with junk yard parts. now they are just for the advertizers.. Back then went junken on saturdays, had a special tool box. now most won't let you in.
 
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