The best way to determine how much your parts are worth is to check EBay. IE I've seen complete working MPEM go for around $ 500.00, the jet pump $ 200-300, seat $ 100.00, hood $ 125-150. Other valuable parts, gauges, wiring harness, fuel, oil tank, carbs, factory pipe, exhaust manifold, water box.
The downside is you have to advertise, ship, collect money, kind of a pain.
Lou