Looks like it could be a diamond in the rough. Rust doesn't look serious, but deal with it as soon as possible. If that's a Carpenter body, try to find out where it was built, I seem to remember something about Indiana-built Carpenters having problems with bad welds at the factory. Easy fix, but requires some demolition work and inspection to find.
Kinda looks like a 7.3 but I'm not sure. An International dealer can probably tell you from the VIN for the incomplete chassis. May also be able to help on the trans too. Here's some basic info on trans ID: