Carlos,
Rear bars are easy to install. It's the fronts that can be a pain. Get a couple of Mark Blands (Engman) rear mounting brackets and supports. Buzzz, buzzz, buzzz
Thenk you'll need some of the factory lower shock bolts.
The front will require:
Gas tank removal
Marks front mounting plates
Holes in the tub (watch out for that wiring harness on the drivers side)
Plates welded in (watch out for that wiring harness on the drivers side)
U-tabs welded on the A-arms...
But HEY Mueller's gonna help you do all that!!
I'm using a one year factory 930 bar (1976). It's 18mm and is said to be torsionally a bit better than most aftermarket 19mm bars (don't know if that's true). I also run 140 rear springs with a factory rear bar. Connect and disconnect as needed...
* Engman, did you get the rear plates fixed? The last set we got had the nuts welded on the wrong side...