New to forum, needing advise

That engine on its own is not going to bring him a ton of money. With more and more people switching out for crate motors and late model motors then they are easier to find. But with that being said it is not that easy to find one that is close to the build date of the car so that makes it more valuable to your friend. Look around and see what other engines are going for.

If you haven't already told this guy with the engine what its going in and that the date is close to the build of the car then DON'T tell him. He will probly use that info to raise the price. If the price sounds high to you then remind him politely that its not an unmolested block (its been bored out) and the crank has been turned under. Also it wont be original pistons cause they are oversized now. And unless it came out of a GT350 then there are some other minor differences such as I believe the motor had an aluminum intake? Its not that these things are bad but they do take away some value. You'll need to rebuild the heads cause you don't want to put those on a rebuilt engine without going thru them.

With all that said it really comes down to what your friend is willing to pay to get a period correct engine. If its a true GT350 then he has a valuable car that will always be valuable and will increase in value. And he likely won't find an engine closer than that. If he won't give you a price then give him one but leave yourself room for negotiation.

Good luck and keep us updated.