Need opinion on complete BB value.

[crossy]

I'm no stranger to picking up parts & marketing them to make a $ to support my part of the hobby. I know chevy engines Big & small and all the numbers that make them important.BUT********* what is a complete 1971 402 out a 71 truck worth that needs only a bottom end rebuild. it is spotless clean as he already had it out once and detailed it. the heads were just done which is probably what made the bottom end go out. Nothing is hurt it just makes noises and i know the lousy piston skirts are probably cracked. It is complete and ORIGINAL from carb down. It has all the correct pulleys & P/S setup with reservoir, exhaust manifolds on it and i know that's what gives it some worth for someone looking to do a swap. I don't have it yet but he wants a wrecked 91 blazer i have and wants to put this engine towards the money. He of course thinks it is worth a lot but I am hesitant[his family owned the 71truck new]. I know there are plenty of people looking to go BB these days but they all seem to be leaning toward crate motors & street rod type hardware. I advertised a friend of mines complete UGLY 1977 BB454 truck here while back and got next to nothing in response. It was an original untouched underhood truck and I thought that would go just for the drivetrain.I JUST NEED SOME HONEST OPINIONS HERE. Am I following the trend the right way? BTW=I am not selling parts off of an engine I don't have yet.LOL thanx , DAVE