440 block what is it worth?

$100 for a bare block is a fair price. I buy a lot of big block motors and most of them turn out to be junk. Therefore I'm never willing to pay very much for a big block. I won't even consider buying a rusty motor as they are almost always junk. Same with frozen motors, or ones with spun bearings.

It takes a bunch of time to tear down a core motor, tank it, mag it, pressure check, sonic check, etc. Most core motors won't pass all of those tests which means you end up with nothing to show for all the work.