whats a scrap truck worth?

[JointTech]

so you guys have beaten into me not to buy an engine unless you hear it run. Thats not going to happen at the junkyard or craigslist obviously.
SO that leaves searching until you find somebody will to sell an engine while its still in a wrecked car or something.

Or buy a car and pull the motor and scrap the rest.

So I need to know what the hulk of say a 73-80 C-10 would be worth minus the engine at a scrap yard.

That would then determine what I'm paying for the engine and how much I can spend on the car/truck.

Also whats the going rate for a 454? I see them for around $700-$1000 on CL and they are already pulled and sitting on a tire with no way to hear it run.

Online chatter makes it seems like I should be able to find one for $400. is that realistic?

If I plan on doing a full build on it would I be better off just finding/buying a core and skipping all the other work?