There are three differences. The ports on a 216 intake are smaller. The carb bases on a 216 are smaller. The spot on the bottom of the 216 intake where it mates up to an exhaust manifold is configured different than the spot on the 235. They look the same at a quick glance, but they are different and require a different gasket.
The first two differences can be made to work for a 235. The ports can be machined out to fit a 235 head with no problems. The smaller base 216 carbs will work fine on a 235 and, in fact, are preferred by some. But the maching of the intake and the exhaust is not possible and that usually spells trouble, unless you use a 216 exhaust manifold, or go with Fenton, or some other brand of headers, that do not require the mating to the intake.
I am running an Edelbrock 216 intake on an 848 - 235 head with Fenton headers. I had the ports machined out and I am running two small base Pontiac Rochester carbs. Everything works fine!!
Hope this helps!
Joe
