I should start at the beginning. I bought my xj about 5 years ago and it was completely stock. I hit a dip in the road sometime during the first few months I had it and the drive shaft u-joint tore through the exhaust. I installed a 2.5" lift after that and never had any problems again. In the spring of 2018 I rebuilt a second 4.0 with .030 over bore and the 4.2 liter crank shaft. I figured with the new stroker, I should up grade the exhaust. The u-joint is now digging into the exhaust once again. Not nearly as bad as when it was stock, but little by little it has torn enough for an exhaust leak. I'm looking for any advice on why there is that much movement.