If you build a motor yourself,
it can be done for about a grand, give or take.
Start with a good Caravan core, (the vans drop their trannies, sometimes before 100k miles) get a 'major rebuild kit' with pistons and oil pump,
have the valves cleaned up and the guides checked/replaced, and you have an alomst- new motor.

Sadly, the truck's worth maybe $300 with a toasted engine- for that price, mine came with $400 worth of new tires on it!

Toby

'89 V6 4dr- '4- Doris'