There will be a few upgrades, like aluminum pistons and possibly a camshaft for a 261 engine, NASCAR connecting rod bolts, and maybe even full pressure oilng of the rod bearings with a late model 235 crankshaft and connecting rods. It's not terribly difficult to put a pressurized 235 rotating assembly into an early 235 block, with just a few minor modifications. There's quite a bit more effort involved in converting a 216 to full pressure oiling, since the block is 1/8" shorter and different connecting rods must be used. It will still look "original" from the outside.
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!