Help with Big Block engine code. 3963512 GM6. Looked up on internet as a 69-70 454 copo. Not sure if that is a good thing? Are there other numbers on the block to help verify this and to determine if it is an LS4 vs LS6?
The stamped numbers on the front of the passenger side of the block deck where the water pump meets the block. If they are gone, then there is no way to tell what it WAS. If the engine has ever been opened up, there is a good chance, the block was just used to build a 454 of some kind.
The 512 block came in both 2 and 4 bolt main. It was used for both 427 and 454 engines. A 1969 512 block with 4 bolt mains could of been a COPO or Corvette block, but being a 512 doesnt automatically make it a COPO.