OK, there are two places in which my original block is stamped with assembly date codes: 1) just in front of the left side cylinder head and 2) on the oil pan rail near the block casting number and casting date. Both are 5L3 (November 3, 1965). Would one of these be for the short block and the other for the complete engine assembly? If so, which would be which? If I were to speculate, I'd say that the one on the pan rail would be for the short block making the other for the complete engine. Thanks for any information.