80K is not a lot for that engine. I'd be inclined to pull one piston assy and a main cap, evaluate the condition of the bearings & surfaces & rings...if all looks good, reseal it & put it in. Bearings are relatively inexpensive & easy to change. My main concern would be that the oil rings were not gummed up & stuck. If you find stuck rings, a new set of rings & honeing the cylinders is within your budget, I think.