Budz71 said:
Just like to know what I'm putting in my car is all. This is my first engine install so I don't want to be telling people it's a zz4 if it isn't. Didn't think it would be that hard to decode if I had the serial number but even gm can't tell me what it is.
How deep is the oil pan? If it has an originally-installed deep sump pan (~ 7" deep; 7-8 qt., w/a kick out on the side), and stock-style v-covers w/two breathers on the driver side, you prolly have a circle track "spec" engine used for racing where the engines are basically run as-is. Some had tamper-proof hardware, some not. Look for bolts or tags that look different in some obvious way- I do not know exactly what was done to make them tamper proof (or more like tamper evident, i.e. it'll show if you jacked w/the engine to get inside it), but something will be obvious if it's one like that. If it's not a tamper proof engine, there will be no such thing, but it also won't say "ZZ4", either.
Otherwise you may have a clone of a ZZ4 engine. I would want to look closely at the cam to see if it was a flat tappet or hydraulic roller (or solid if aftermarket/non- GMPP crate engine), and to see what the numbers on it were. With that info and finding the deck height and the piston volume, the compression can be calculated (the nominal head volume is known). Knowing the CR will tell you if the cam is compatible.