Look for the block casting number just above the oil pan flange on the passenger side near the front of the block...it' will be under a layer of crud.
CON4 is of no value to us, it was the conveyor number the engine casting was made on and it helped identify where to look when problems in the casting process happened.
Casting date code G 5 7
G = July
5 = Day
7 = Year (1957)
So it looks like you have a replacement engine done under warranty as it got the original serial number transferred to it.
Mike B
