Yeah, that's because I don't know. It was a basically stock rebuild other than the hydraulic cam. At the time the factory solid cam wasn't available. I've never heard of anyone else using the TRW pistons (this was back around 1992 that I built it) but I assume they were intended to maintain the factory CR (I know people say the Egge ones don't). I have about 90K on the build -- it has been dead solid reliable. I even put in a track day at Willow Springs in 2010. I used lead substitute until it was well broken in, then just 92 octane. The engine is out of the car now -- I refreshed the heads and had them mildly ported while I was at it, and replaced all the soft plugs as one had started weeping. I also degree-ed the cam just for fun (and because I replaced the timing set), and to find out how I had installed way back when. It was installed straight up (plus 4ยบ advance built into the grind).