Have a small block that I recently purchased and was told it was a GM crate motor. Upon further inspection I found the casting number 3970010 on the block which I see online as a 69-79 350 2 or 4 bolt mains. Only other numbers I see in that area is a K 1 above the oil filter casting. The numbers on the passenger side deck are confusing to me as they are 151198602 with a space separation and K04. What are these numbers and the K04 designation? The heads are 333882, 74-80 76cc.