I have just sent an email to CHI to get some clarification on this intake manifold question. I believe that the information that CHI has about the 3V heads may be outdated or they are looking at getting a perfect port match. The 3V cylinder heads have a smaller intake port than a factory Cleveland 4V cast iron cylinder head. The 3V port size is very close to the 2V CHI cylinder head port and the factory 2V cast iron Cleveland head. There are several intake manifolds on the market today that should bolt up to these heads. Edlebrock makes an air gap, which I once had and used on a set of CHI 2V heads that I had on my last engine. Trick Flow also has come out with an intake manifold for their aluminum Cleveland heads, which is also looks very much like the CHI 3V heads. There are a few other options for intake manifolds also, but I didn't get too far into looking.
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