The biggest problem on the 80 CJ5 is the frame at the main eyes. The frame gets a lot of rust in these spots. The front of the rear wheel well where the rollbar mounts to the floor. The rear wheel splashes all kinds of stuff there. Then general rust. If it has carpet or floormats pull them up and look at the floor. If it's carpet my geuss is the floor will be rusted. Good luck
86 CJ7, 258, t18, D300, D44's 4.56's, Detroit front, Warn shafts and CTM joints, spool rear, SOA, SRS, waggy springs, 6 point cage, Warn winch, 38" Tsl, Allied beadlocks.