340/440 worth

I'm new to mopar but not cars. I dont know squat about what these mopar motors are worth however I respect the idea of passing on a 340 for 340 car owners that need them. If I find one to buy either just a block( whats that worth?) One thats together but not in a car? One that I can hear run? Thats 3 apraisals I need. Also same thing but on a 440. Please help so I dont get screwed and can maybe pass something good on to another FABO'er.

Skullz