I have a 66 Mustang with a door data tag says it's a code A engine. PO replaced the original intake 4vv carb with a 2 vv. The intake was from a 67. I am putting it back to original. But after removing the intake and carb I found a stamp on the block and now I'm thinking this isn't the original block either.
The code I found is 6A4 and then a letter or number I can't read. Looks like the top of a 'B' or the top of the number '8'. Door data tag for the date is 03M (Dec. 3, 1965). I'm guessing the block code 6A4 is for Jan. 4, 1966. Is this right? If I guessed right it isn'tthe original block....