I totally agree with Mike and Bob.

My $.02 FWIW. What you will find are guys who want to low ball you with "Jeg's has a new 350/350 ZZ4 for $4100 bucks, why should I pay you $xxxx for a 'used' engine that may be running now, but...."?

(Chevrolet Performance 350ci/355HP ZZ4 Engine - JEGS)

Unfortunately, and as you have probably heard way too many times, 350 Chevy's, regardless of which version you have, are like a belly button, everybody has one.