Consider a post 92 1 ton. They have the 4l80e transmission, TBI and bullet proof axles. I bought one not long ago for $700 that had 120K miles on it. (The early 90s vans have a 6 digit Odometer so you can actually tell how many miles it has on it.)
https://tampa.craigslist.org/hil/rvs/d/tampa-ford-e350-motorhome-party-bus/6934138461.html This has potential.
I have a '99 E150 Conv that I can give you a screaming deal on. It's past it's prime but with a little elbow grease it could still be a good track van.
This may be more than you want to spend, but it's a good deal. It's newer also. https://www.auction.utk.edu/APViewItem.asp?ID=11192