Valve Train and top end
I was going to get the COMP Cams K68-231-4 Cam and Lifter Kit
that included the timing set, lifters, valve springs, retainers, locks, and seals, but after a little research in my spare time at work, I found that:
K-kits will only work in 1964-88 models due to different valve stem.
IE, they were only designed for the AMC 258(4.2L), so the parts pertaining to the valves them selfs will need to be obtained elsewhere. COMP recommend getting a spring kit from Mopar Performance. I already have a brand new set of lifters soaking in oil from when I thought I was going to replace them in the XJ, that didn't happen, and I couldn't return them since I had already put them in oil. If I didn't already have the lifters, the
COMP Cams SK68-231-4 Cam and Lifter Kit
was what COMP recommended, it would be the most complete set up they offer for the 4.0L. I will also be running Harland Sharp roller rockers.
The head came off an engine out of a 04 Rubicon with reportedly
about 13K on it, specifically chosen for the TUPY casting revision. I'm in the process of porting and polishing it. Gasket matching it and just trying to straiten out the ports as much as possible, as well as help speed up the air flow. I'm not pushing for more air volume, but more velocity for better low and mid range torque.
I'm also cleaning up the combustion chambers a little, so I will be CC'ing them as well. Once I can start getting solid specs on everything, I may make a few small changes to the combustion chambers to get the compression ratio where I want it.
Intake is the newer style off of my old 01 XJ. I will be match porting it, and only cleaning up the last 2-3" of the runners since I can't get much deeper with the grinder I'm using. I also have a little bling in store for it, just because.