[brighton911]

Dave, I can say that a 8 thou difference in assembled height on one cylinder meant the cam bore was distorted enough to cause some binding. So yes, it matters a lot. I determined the high one by bolting just the cylinders down and using a straight edge across the tops. The cylinders were part of a 3.4 package that I bought so not original to my car. Once I adjusted the height of the tall one, all was well and the cam turned effortlessly.