Market Price for an Original HiPo Block ? ...

A question for the forum. Recently I purchased most of a disassembled K-Code engine; block, heads, crank, caps, rods, etc. The block is VIN stamped and I have been able to contact the owner of that particular Kar. I offered the entire group of parts. I believe the date codes to be close enough that the most significant components to be original to the engine. He wants the block only. What is a fair price for the block? Opinions appreciated. Engineer