I do not know about your area, but around here, every given week, there are 5-6 Isuzu Troopers selling for $700-$1200. Half of them usually have a blown tranny and the other half has blown motor.

If my engine was to go TODAY, I would go and buy one of those donor cars, strip them of them of what I want (or can sell) and junk the rest for around $200 worth of scrap. This is the by far, the cheapest way to get a used motor