Running a 216 intake on a 235 requires a set of stepped-down alignment rings to keep the manifold and head in the proper position. Running without the rings increases the possibility of a vacuum leak. The rings don't actually seal vacuum- - - -they just keep the gasket positioned properly. The 216 intake will increase low end torque a little, but it will rob some top end HP, even with the correct size carburetor. Most Carter YF carbs have a slotted throttle body that will fit either a 216 or a 235 intake.

Run- - - -do not walk away from anything "Clifford"- - - - -the only thing they're really good at is making your checkbook need CPR!
Jerry

Edit: If you're planning to attend the stovebolt shindig in Townsend Tennessee this year, I can bring a 235 intake with me- - - - -I've got several of them.

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!