complete 1971 340 WIW

Somebody stopped by my shop yesterday looking for some parts with a 1971 barracuda. He was looking for a bunch of stuff and then mentioned he also might want an engine since it currently has a 318. He saw my engine on a stand and asked about it.

What I have is a 1971 (6-30-70 casting) 340 that is complete from pan to carb. It still has the original intake 3512100, Thermoquad carb, J-heads, and exhaust manifolds. I know nothing about the inside of it other than the guy I got it from in trade said "it ran great when it was pulled to redo the car it was in."

Well, that must have been when he shoved it in the corner 20 years ago because there is no way this thing ran the way it looks now.

I am not married to the engine and I basically got it for some labor. The big question is, what is a fair price nowadays for a complete but needing to be rebuilt 340 motor?