I have a gm block, supposibly a zz1. I have engine numbers gm 5.7 LG with 14093638 I did research on it I just can't figure out how to tell if its the zz1 in was told. Any help would be appreciated.

 

That was a very common casting that is one-piece rear main seal, could be either 2 or 4 bolt main, may or not have the roller lifter provisions machined.

If it was a ZZ1, from what I've heard it should have "ZZZ" stamped on the serial number pad in front of the passenger side cylinder head. It should also have 4 bolt mains, and the roller lifter provisions machined. And, the mechanical fuel pump push rod and oil return drilled.

If all you have is the bare block, then it really doesn't matter much. Other than it could be a 2 bolt main, and may not have the roller lifter provisions machined and the mechanical fuel pump push rod and oil return drilled. The casting was their bread & butter 350 block, used in anything that came with a 350, including performance crate engines and fleet replacement engines.

If you have the complete short block, it should have a steel crank and "pink" rods if it was a ZZZ engine.

 

Awesome thank you

 

So, what do you have?