Ok for anyone who wants better braking power in there 4.2 this is for you.
I got on eBay I bought a stock 95 jeep Yj brake booster, mc and proportion valve.
Total cost 150.00
I wasn't going to install it after reading all the stuff in the net. That says it won't fit due to clearance issues with the carb.
Well I had to try for myself
I took off my mc and brake booster. And to my amazement the 1995 dual diaphragm brake booster was a simple bolt on for my 1990 4.2 I didn't even have to flare the brake lines nor change the nuts that thread into the proportion valve.
I'm on 33's and the jeep stops better than any other vehicle I have ever drove
Well worth the mod
Here's is some pics