My tired old 4.2 is fouling the #3 or #4 (I forget which -- haven't looked in a very long time), and I am thinking the trouble is valve guides/seals/stems, or any combination.
Instead of just replacing the seals, I was goiing to take this opportunity to pull the head and swap in a 4.0. I did the Hesco fuel injection several years ago -- early 2000 -- and installed a Borla header at that time, and this made a huge difference in performance.
Clifford is not very far from my house, I could easily go there and get my engine parts, but the checkbook is not bottomless so I need to get this done on a shoestring. Clifford makes good stuff, but I assume they are probably pricey. I am not considering a complete rebuild, only a head swap.
You guys that have made this change, how much did it cost and where did you acquire your parts? Another thought -- does my Borla header for the 4.2 fit the 4.0? The intake should be okay, shouldn't it?
PS Due to work issues, my Jeep has not been out of the barn for a couple of years. There is light at the end of the tunnel though, and I may be driving my Jeep again to work across town. Since the Jeep has not been out, I have to begin anew my observation of the plug problems, and other stuff that needs attention ...