I had a lifter that was going bad on my Jeep after 421,000 miles, so I ordered complete set of the Crowns to replace them. Comparing the new ones to the old, and they are identical. As with all lifters installation was a snap, once I removed the head on the inline 6. I used plenty of assembly lube on the lifters during installation and upon startup experienced no problems, held idle at @ 2000 rpm for couple of minutes and drove vechcle easy for first 500 miles. So far no problems.