Roy,
I used to remember the exact dimensions but as I sit here they don't come to me. The ports are smaller on the 216 head and intake and the stud spacing is less on the 216 and the 235. I believe the stud spacing on the 235 is 2 15/16.
The ports on the head are spaced the same, so some people do mix and match the manifold and heads but I would think for any real performance you would want the 235 intake with a 235 head.
Bill
