I use a flat tappet cam and shell lifters. I removed the intake manifold and had it pressure tested for porusoty before I had it ceramic coated. Afterwards when reinstalliing the manifold I pulled a couple of the heli-coilc for the rocker stands. Then I noticed that I couldn't remove a couple of the lifters. It turned out that I had flattened two lobes on the cam shaft and mushroomed those two lifters. I removed the engine and had it gone through no real damage , the cam came out normally but those two lifters had to come out the bottom. Everything got caught in the filter. The
Oil pump may have suffered but I was going to replace it because of wear on the hex drive. I bought another set of shell lifter plus two more and a new cam shaft from Comp Cams and pushrods from smith brothers in Org. I ws really concerned about break in procedure. I heard about the ZDDP later. Wary back when solid shell lifters were all I used never had a problem myself, but the oils were different then