the reason i say 74-76 500 is the 472 was done in 74, and with the eloctronic ign showing up in 73-74, it is just a good guess. Of course the only real way to tell is to dissassemble and check it out. I am attaching this page here for some pretty good Cadillac engine reading.
http://www.crankshaftcoalition.com/w...utor_and_wires