I've got a '84 Mazda B2200 with the industrial all gear drive diesel. It has over 400,000 miles on it and all I've ever done was to replace 2 water pumps and an alternator. Its one tough engine! It still goes 3000 miles between oil changes. Engine is great but not the body. The wife won't ride in it anymore. She says its ugly, but at 52 mpg highway I just don't care. I almost lost her a few months ago. She was leaning against the door when I made a left turn and the door flew open! She still refuses to ride in it to this day! Good luck on your find. I'd love to have a low mileage version. Mine had 160,000 when I bought it. It has been the best and cheapest running pickup I've ever had.
Mike