Some people think I paid too much for my 302/AOD combo at $1200 shipped to me, complete with the
entire car's wiring harness and ECU. But it had a verified 32,000 miles on it, the car reflected that, and I got a 12 month guarantee it would be a good engine just by talking to the guy on the phone. I even had him put it in writing. They'd send another engine to me of equal value and mileage if there was something majorly wrong with mine.
Truck runs like a scalded dog to this day and burns no oil whatsoever. Not bad for a junkyard engine from the era when they came with forged pistons. (I had always planned to use a power adder sometime in the near future)
Now, the AOD ended up having a smoked OD band after installing it, so I switched to a manual trans, but I still sold that AOD for $200 because it was a low mileage trans and those are getting hard to find. I really wanted a 5spd anyway, so it was kind of a blessing the AOD had the OD band smoked. It made me spend the money for a brand new Modern Driveline front shift rear socket T5Z.
Sometimes you just gotta locate the lowest mileage 302 you can find and bite the bullet and pay for it. Quit dreaming and start building.