Hey Southern Comfort, Welcome to the few, the CJ-6 owners. I too am doing the power upgrades to my 6. Mine is a 75 model with the 258 6 cyl. That's neat you got a 304 model. Does yours have a tailgate, my doesn't and I haven't seen another one with out.
Unfortunatly, my fathers car was totaled out and we bought it back from the insurance company. What I found was the power steering box from the 73 Pontiac Grandville was almost a direct match too the power boxes used in the CJ's. The difference is the CJ units have the numbers 76 cast into the housing. This one doesn't because it's a bigger bodied unit. The mounting holes are a dead match and the splines on the steering shift are a match, so is the over all length of both the units body and the pitman arm. The tierod hole is correct and the arm has a slight drop to it where the CJ arm is straight. The only different is one of the hose fittings (return line I think), but there is an adaptor for that. The few times I drove the Pontiac, the steering was incredibly easy to turn (ie very powerful for such a big car). You could almost blow on the wheel and it would turn. This should be a great box. The pump is the same too, but I'm getting the proper brackets to fit it to the 258. I'm also swapping in wide track CJ axles to gain disc brakes and a wider track width as well. I haven't figured out the power brakes yet, but I do have the Pontiac set up in case I can use any parts from it.
1975 CJ-6 1983 CJ-8
1986 CJ-7 Laredo 1986 TJ-7 Trail Jeep
2003 Inca Gold TJ Rubicon