There are other differences besides bore size between a 1950 216 and a full pressure 235. One is the "oil distributor" on the driver's side, something a full pressure engine doesn't have. 235's also have a taller block dimension from the crankshaft centerline to the top of the block. A 218 cannot be turned into a 235. Boring a 216 for 235 pistons makes it a 224.
Jerry

"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!