The engine block casting number indicates a 1976-1979 305 cid, 2 bolt main. Without the engine ID number, normally located on the pad just forward of the passenger side cylinder head, it may be difficult to get more specific. What vehicle was the engine taken out of?
About the rebuild, have you called Aaron's Automotive? Their phone number is (417) 831-5257. They may have some info for that serial number.
