Small block chevy identification

I have a small block GM 350 4 bolt main which i believe to be a 1970 LT1. It has all
the proper casting numbers. 11 to 1 pistons cast#3959456, crank cast#1182, block
cast#3970010 with a stamp on the block behind alternator of CE233789 which i
believe to be a counter exchange engine. It has the pink connecting rods with the pan
that bolts to the main caps and another that goes in the valley for the push rods to go
through. What i don't know is what does the stamp on the block where the starter bolts on mean. the stamp is V4 72921. I do also know that i am the third owner and that the engine as of yet has never been on the street. Only on the strip. First in a 58 vette and then an 84 camaro. If any one can help i would appreciate it.