This summer it will be too hot to go wheeling in the desert. A perfectly good time for a potential 4.0 top end tear down and refurbishment. My sled runs fine, 90K miles, no smoke, misses or leaks, but I have one lifter that occasionally goes Bojangles and does a minor tap dance. That noise tends to go away after running about 5 minutes. I just added some mechanic in a can to the crankcase to see if that will revitalize it, but I was born under a bad sign and I do not expect the hydraulic gods to smile down upon my sinning soul. I am OCD about components functioning flawlessly. All that said, do you know of a quality top end kit and would you be inclined to do valves and cam at the same time? Timing chain and gears? I have not check the compression and will, but I have no reason to believe it is not tight.