If you plan to go back with Babbit rods, PM me. I have a big stash of reconditioned ones- - - -a few standard, and several undersizes that I can hone out to STD dimensions (or a few thousandths under). Something like a .005 under would be possible, and scrape-fit it to a crankpin that's been polished round and smooth. A little creative tinkering is possible with Babbit- - - -something that would be impossible on a precision insert bearing. Aluminum 235 STD diameter pistons are a drop-in fit on a 216, with a 60 overbore- - - -gives you 224 cubic inches (and a bit more compression). Replacing the cast iron 216 pistons with aluminum also reduces the centrifugal load on the rods and lets the engine accelerate better. It was a very common modification to a 216 50+ years ago.
Jerry