Good points about the diffrerence in stock and high-performance cams, Joe. Another factor that's often ignored is the expected lifespan of some of these engines. The round track engines I built for a lot of years had more "wear" built into a brand new engine than a 200,000 mile street engine. It was routine to run .005" skirt clearance on forged pistons, and .002" to .003" clearance on rod and main bearings. The engine would sound like it was tearing itself apart if it had been run with mufflers. Solid-lifter cams with big clearances were noisy, also. I could hear a gear-drive cam half a track away. With open exhausts, we couldn't hear the hammering coming from the crankcase. Ditto on cams and lifters- - - - -if the cam made 1,000 laps around a 1/2-mile oval without wearing out, we considered the engine a good one. Some survived the whole race season, others got swapped out at mid-year. People who do race engine stuff to street engines should be willing to accept lots of noise, and very short engine life as part of the equation. Race parts assembled with street-engine clearances don't work well, either!
Jerry
Last edited by Hotrod Lincoln; 03/01/2011 6:17 PM.
