$1600 is a bit high for a used one, especially w/80K on it it would be do for service not long after you put it in. Unfortunately reman'd ones here in CA run about $2500. Finding a used one that is in need of a rebuild would be the cheapest way to go. I know a few people that have gotten good engines from Rising Sun Engines

More than tread lightly. Leave it like you were never there, nor anyone else.
'90 X-cab 4.88's 33 BFG AT's, rr ARB, Headers, Ignition upgrade, cold air induction.
'91 X-cab 5.29's 315's BFG MT's, rr ARB, custom bumper and flatbed