Hy mauricioaglr, that picture is of the casting number for the cylinder head, not the engine identification number which is stamped into a machined pad right behind the distributor. I did some more research, and the numbers I came up with are:
six volt coil, AC p/n U520
twelve volt coil AC p/n U505
early distributor cap, 52 and older AC p/n D301A
late distributor cap, AC p/n D307, hope that helps.
