my buddy has a 90 xj with a weird brake system haven't payed much attention to it, and is wondering if we can take a normal xj brake system and replace it, he says its like a abs system with no brake booster i'll see if i can get a pic of it soon any help would be awesome!

 

I had a 91 XJ that had that system, it is the bendix 9 ABS system, and I would assume that you are asking about swapping to the booster setup because the air pump that supplies pressure burnt up and it is like stepping on a brick to stop? That is what happened to mine, in the dead of winter.
The answer to your question is yes it can be swapped, I actually got my entire system (booster and vacuum line to manifold, master cylinder, and proportioning valve) out of a Pick-a-Part 95 XJ. And swapped them out in about 4 hours, I actually still have to master cylinder and computer out of the bendix system. The booster bolts in exactly where the abs master comes out of. The biggest pain was pulling the high pressure tube that runs along the back of the firewall, but since I wasnt going to use it I just cut it in two. you will have to get adapters to fit the proportioning valve for the lines that run to the wheel hubs, as the bendix system is different size. Hope this helps you get a start.