A quick fix for a 216 with badly rust-pitted cylinder walls is to bore the cylinders 60 over and install standard bore aluminum Chevy 235 pistons. They're a direct drop-in fit once the cylinders are bored and honed to fit the pistons- - - -same compression height, wrist pin size, etc. The .060" overbore gives you a displacement of 224 cubic inches, there's a slight increase in compression and the aluminum pistons are lighter weight than the cast iron ones and they don't beat up the Babbit bearings as quickly, so shim adjustments aren't needed so often.
Jerry
