[Woodz428]

I just finished a breakdown and documentation of a 427 service shortblock. It had no casting numbers other than the date code which had an omega sign for the year code. It was crossbolts and side-oiler with the ability to run hydraulics. That may be what you have, a service block. This one didn't have the ribbing I have seen on some of the later ones. The omega would be the year it was cast, but I don't know the service date codes. I surmised it was in the early 70s. It had the 12.5-1 pistons with forged crank and regular bolt/nut rods like the 406,early 427s and the CJ.