If you don't have a level pad to work on, borrow someones flat bed trailer. You can level the trailer bed with jacks pretty easy. Once on level ground, measure frame to floor in all four corners. It's likely the springs and bushings are worn out along with cab mounts. Add up all the wear and you can have a pretty good lean.
I went through a mess getting my truck licensed in Missouri due to title problem. My brother in-law purchased the truck in the early '70s and never transferred his name to the title, so when I bought it in 1999,the original owner had passed away and the title was no longer valid. Just be sure your title is good before spending a lot money or time on the truck. I had to get a the Highway patrol to verify my truck before getting it titled, they were check serial numbers of the engine and transmission. They were not worried about the other aspects of the truck, just looking for stolen pieces. I have had YOM tags since 2001, so no inspections since.
My truck had springs so worn, the bushings were gone and the pins were riding on the leaf itself. On top of that, each leaf had worn a groove in the spring above it so deep, the springs could barely slide. It was like solid springs at each corner. The truck came from Hillsboro KS, a heating company used it for 30 years traveling the Flint Hills area.
