ok, i just got a 500 big block for my build up project. cool, right? anywho, i can't seem to figure out what year it is. i've read several threads on this and looked at the engine identification web page. the block cast # is 1495200. the head cast # is 1602493. the crank cast # is 1496793. the pistons are pretty flat with a very, and i mean very slight indentation of a perfect centered circle. any input would be a great help. thanks.