ok,well i finally got the motor torn down to the bare bones and ive been triing to figure these #'s out. i figured out that this #2536030-318-13 is a LA block from 67-75.but i cant figure out what the 13 is in the sequnce.its stamped 12-7-70 we know what that is also.no the question i have is are the #'sfor the heads #2658234-1 these numbers say its a set from a 1967 273??closed chambered-int:1:78 exh1:50. they also have truck stamped on them.what is the -1 and are these any good?why would they have used these from that 273?plus there is a AAQA stamped on the front of the block any ideas??