Based on your new info you have a 1978 350 cid Chevrolet block cast on June 20, 1978. The engine was assembled at the Flint engine plant on June 22, 1978. For what model I don't know, the TDB engine suffix code doesn't show up anywhere for 1978. Anybody else know? Dave, can you clean (remove the paint) from the engine pad and recheck the numbers/letters? This might "clear" things up. Also, I can make out only two of your photos.