My truck has had a tick for over 100,000 miles. The dealer mechanic said all hemi's have it. The truck still runs but #7 cylinder has developed a miss. Changed the coil pack and plugs and still has an intermittent miss. Check engine light comes on for a bit then goes out. The other day the noise from the engine was loud enough the dealer service manager said he could hear me coming. I think I'll do the 6.4 cam, all lifters and springs just to be safe. I'm religious about 3-4 thousand mile oil changes but this time I changed to synthetic oil and that may not have been a good thing.