First I have a 1989 Firebird Formula with 5.7l,

I have a transmission that is out and will not go into reverse. I looked at rebuilt or rebuilding it but have seen in my area on Craigslist 700r4 for sale that are rebuilt and cheaper.

I need to know what transmissions will be interchangeable with this such as Chevy trucks or years.

 

Unless the transmission is out of a Camaro or Firebird it's not going to have the mounts for the torque arm. Sometimes you can get away with changing the tailshaft, but it's not really worth it. With exception of the Corvette, most other cars that had the 700R4 had a softer version. Your current transmission is a better choice for your car, just shop around and have a good shop rebuild it.

 

Your trans. mount is behind the pan on the main case.
Your torque arm mount is on the tailhousing.

Most any third gen, car or truck 700-R4 trans. (pre-93 trucks, pre-94 cars) will work and accept the TCC wiring plug.
You'll need to use the right dipstick tube and the thirdgen tailhousing. Keep your '89 VSS and speedo gears off the old trans. to use also.