this is the casting number on my block. maybe someone else can get more info, but so far i think i know its a 1971 ford motor
D1AE-6015-AC
and i think the ac means something about emissions?

 

D1 says it was FIRST used in 1971, there also will be a date code somewhere on the motor like a "4C26". The AC has nothing to with emissions, I think it has to do with revisions to the part number. AA would be the first casting. Number Dummy is the expert on this.

 

The AC is a suffix. It likely is just a revision number. Not sure whether you are looking at a casting number or a part number. D1 indicates initial design in 1971, A I believe is engine family, E means engine part, 6015 part type (as I understand it) and AC would be the current revision.

 

well thats whats stamped on the block where the starter would be covering it up...figured thats where it would be. ill check it out and see if theres any other numbers printed on it