What are the LD4B manifold worth?

It's worth exactly what the"buyer" pays. I have bought running 340's for $250.00 bought a 68 complete hemi for $600.00 but that is irrelevant. If you want something and it's in your ball park do you really want to wait for it to drop in price? Lots of guys will try for years to build a 440 A body that is completely out of their reach when they could put a small block in and drive! It's all in what you want-but the other guy has every right to price his parts how he wants.