It's true, most small block Chevy engines have no markings from the factory. SOMETIMES, there's a number stamped into the cap on the bolt "flat".
If they are truly the original caps from that block, it takes about 15 minutes for a machinist to "sort it out". Not complicated, but helpful to have the correct measuring tools, in this case, a bore gage, set to the housing bore size. If all the visual indicators that Bob mentions are "there", making sure everything is "round and straight" will take care of it.
Last edited by Mr. P-Body; 04-04-2013 at 08:24 AM.