I have a '79 cj5. When I got it, it had manual brakes. I swapped in a jeep cj power booster/master cylinder setup. I also went from 32" to 33" tires. It stops real well.

There are writeups on doing a YJ booster installation in a CJ. It's supposed to be a step up from the CJ booster.

Moses Ludel says says NOT to put too big of a master cylinder in a small vehicle.

'79 CJ5,401,t-18/d20,dana30/amc20(Mosers),GM HEI, Edelbrock Performer intake,Holley 600, ps/pb, 'glass tub/1pc. tilt nose, 33x12.50x15 BFG T/A's. Lots more to be done...