Intake manifold porting

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Heardatbeat

Well-known member
Joined
Nov 22, 2016
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Location
Washington
My Car
1971 Mach 1
Afternoon everyone. I got a buddy who has a 351C 2V Holley Street Dominator intake manifold and he is willing to sell it to me for dirt cheap. My question is can I have this intake ported to accept my 4V heads or would it be shaving too much material?

 
In my experience there is only enough material right at the end of the port on the intake manifold, the runners going up to the plenum are pretty thin. All you can really do is port match the ports, but be warned, it makes sealing the intake more difficult. I have never understood why there is not a better selection of intakes that match the ports of a 4v head. The Blue thunder is almost unattainable, the Offenhauser 360 is really wide open inside, (no port velocity), and most of the "real" Boss intakes are a goofy spread-bore. I have always hated the port mismatch of most of the popular Cleveland 4V intakes. Not to mention, very few fit under a Ram-Air hood!!! Good luck!!

 
The 302 version worked well for mild builds in the 80s. I don't know about the 351C version.

Here is link with pictures. http://351cleveland.wikifoundry.com/page/Holley+Street+D+300-12

 
Thanks for all the replies! Turns out it might be better to keep the intake ports small to create velocity. But my question would be... Do I get an intake gasket that matches the heads? Or one that matches the manifold?

 
As long as the 4V gasket seals the intake, that is what I'd try to use. Chuck

 
It happens a bit on mild builds, gasket sealing is the trick as Chuck said. The intake port being smaller than the head port is not a huge issue as it works as a sort of anti reversion. Not the most desirable set up but you can make it work.

 
I got a 750 CFM carb I bought from a member here and I am gonna pair it with the Street Dominator intake and a one inch spacer. I am basically gonna tinker with it until I get the desired effect (go faster). Hahahaha

 
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