If your 216 pistons are the domed type, the flattop 235's will lower the compression slightly, but that will be offset by the bigger bore. Just don't try to replace a flat top with a domed piston- - - -there's a possibility of head to piston interference.
Jerry
Good to know. The 39 does have domed pistons. The 40? I do not know yet. Hopefully I can get that one home soon.
Harmon
