the unibody rails are rotting to the point that there are huge holes in them around the cross member and where the lower controle arm bracket is any ideas how to fab up a frame for this ? and i want to weld up a long arm kit i dont know which way to go seperate upper and lower controle arms or weld the upper controle arms to the lowers like a 2 link set up with adjustable hiem joints which would be better

 

Well first, do you think this XJ is even strong enough to withstand the abuse of wheeling?
If she's strong enough, id start by using a grinder to cut out all of the rotten areas of the unibody so it doesn't spread. Then weld steel plates to patch all the holes in the unibody. I'd also brace up and reinforce stress areas on the unibody to make sure nothing buckles later on. After that's all done, just to be safe run the dual link setup. It should work just fine after your unibody is nice and strong again!

 

If its rusting that bad it might be a good idea to go on craigslist/kijiji and find a Jeep with a blown motor and swap in your drivetrain and work off that.

If its fixable I'd cut out the pieces that are rusty, patch in a new piece then install "frame" stiffeners over top. If you do it like that, it'll be stronger than stock.

Theres a point where the work isn't worth it though, judge carefully before dumping more cash into a unitbody that might not be worth it.

 

All the above & take a good look at your floors prior to spending any time or cash on the project.