exhaust manifold bolts?
Soak them up for a couple of days in penetrating oil, keep doing it for a day or two every 6 hours. Best way to get them out, then when you loosen them a little, then tighten just a little, same process over and over. to try to break free the rust, if not heat them up like the other post said and grin and bear it.
85' CJ7 Laredo, 383 GM, Turbo 350, NP 203. SOA, 2" frame lift, 34" TSL swampers, Dana 30 open, AMC 20 w/ detroit locker, 4:10's, 1 Piece Mosers, 35" boggers to abuse when needed.