"Setting the deck height to zero above the piston appears to cause superior fuel/air mixing on the compression stroke. This better mixture then seems to burn faster after ignition, and the faster burn means the ignition pulse can be delayed slightly for optimum power. The delayed, or retarded timing, means we are further from detonation, and can then run increased CR on the same fuel. It appears to be a win-win deal. We were able to reset timing from an optimum point of 34 when running about .015 clearance, to only 30 when the deck was cut to zero. That appears to be very significant when shooting for best possible power on a given quality of gas, and I note in the just received Feb, 2000, issue of Popular Hot Rodding, the latest GM LT 1 engine is using a positive deck height of .007 to .010"(piston above the deck). Of course, we don't know the total clearance, but it certainly indicates that GM also feels the close deck is productive. Jim Hand "
