20,000 miles ago I put reman short block how does that affect value

97K miles is still pretty good mileage from a selling standpoint, and you have a new engine with only 20K miles on that, so it should boost value. (Why was the engine replaced, was there a defect or abnormal wear?) You should ask for the Blue Book value plus SOME of the reman engine cost, as you won't recover all costs for new motor.

I would say a small bump in price but the original engine should have been good for way over 200,000 miles.

ford had a bad batch of 5.4 due to oil not being circulated . my motor went out in the so-called end of warranty thus the new reman block at my expense and with that 77000 mileage