Have a 216 engine from 1950 Chevy 3100. Bought a Rochester off ebay and my mechanic doesn't like it because it leaks gas and he says electric choke is better.
An electric choke IS BETTER.......than a poke in the eye with a sharp stick!!! (but not much better)!
Personally, I remove automatic chokes from those vehicles of mine that came with an automatic choke, and install manual chokes.
As stated above, the 216 manifold mounting is 2 11/16 inches bolt center to center, whereas the 235 manifold mounting is 2 15/16 inches bolt center to center.
Carburetors for 216's are MUCH easier to find than carburetors for 235's.
You might show the following article to your mechanic:
http://www.thecarburetorshop.com/Automaticchokes.htmHe/she probably won't agree, but the article might provide "food for thought".
Jon.