Since certain sizes of main bearings are getting scarce and expensive, I'm modifying the block to accept mains for a small block 400 V8. All the crankshaft journals end up the same diameter (slightly smaller) for less rotating friction. That procedure involves fitting some reducer sleeves to the bearing bores in the block, line boring the block, and fitting a permanently-mounted bronze thrust washer to the #3 main bearing cap.
1.94" intake valves for a spray-oiler 235 with a Powerglide and 1.6" stainless steel small block V8 exhaust valves, plus some pocket porting will make the 216 cylinder head breathe a little better, but there's not much that can make any stovebolt a tight-winding screamer- - - -build the engine for increased torque and gear the rear end appropriately.
