what kind of V8

I'm thinking of buying a 350 v8 I found one in the local classified. The guy said it is a Chevy 350 V8 Crate. Not much help other than that. How do I determine if it a Vortex, ZZ4 or first gen 350. I'm new to this so is there a p/n to look at or can I tell just by looking at the block. I'd eventually like to research the specs.
Any thought would be helpful.
Thanks.