216 and 235 pistons have the same wrist pin diameter and compression height. The only difference is the bore size. Standard bore 235 aluminum pistons can be fitted to a 216 block by boring the 216 1/16" oversize (0.0625") The advantage to doing that is a lot less stress on the 216 Babbit rods- - - -the lighter weight aluminum pistons don't pound the Babbit out and increase the oil clearance as much as the cast iron pistons do.
The "sneaky Pete" 216 I'm building is going to have a 235 crankshaft and pistons in it, a "Corvette 235" cam, pressure lubricated rod bearings, and 292 connecting rods to compensate for the lower block deck height. It will also have an oil pump for a 250, and the full-circle lip seal at the rear main bearing. From the outside, it won't look any different than a standard 216.
Jerry
