I rebuilt my 496 bbc engine back the way it was when I bought it (engine came with paper work of all the internals). I installed new gapless rings, new cam (found 1 wiped lobe on the cam) and lifters(found 2 worned lifters), all new bearings. I also installed 2 new valve springs that I found with broken inner springs. I didnt touch the carb and I sat the timing (38 degrees) back to where it was before the rebuild and Im also shifting at the same rpm. I went to the track tonight and she lost .06 in the 60 foot and 1.7 off of my 8th mile ET. Im wondering if I should get this thing dyno tuned again. I was thinking she would run alot faster since I found the 2 broken inner valve springs, wiped cam lobe, and 2 worned roller lifters during the rebuild which cause the engine to pop going down the track at high rpms in high gear. Im stratching my head wondering how could a engine with 110 passes on it with a few worned parts run faster than the exact same engine with 2 passes on it. hhhhhmmmmmm. Any input???