I pulled this motor from a 71 Elcamino. I'd like to know what it is for sure. It's a 4 bolt main The casting numbers by the distributor are: 14015445 (78-1978) The engines front pad is stamped: CES133564 The heads are: 386781 -Oval port - open chamber What I really want to decode or understand is the front pad number. CES133564 Does CE stand for crate engine? Can this number be traced to a specific GM part number? Thank you!