All this polishing probably sounds counter to the practice of cimpling the combustion chamber. Dimpling has been show to put wet flow back into the air flow and improve combustion. We do not recommend dimpling, but do suggest cutting a small discontinuity close to the valve seat to turbulate wet flow. Some bench flowed cylinder heads encourage fuel separation at the inlet pot. If a small step is added at the valve seat to force the wet flow over the resulting sharp edge, fuel will reenter the air stream and give you the same affect as dimpling only without losing the benefit of a completely polished chamber. As you reduce wet flow you will improve combustion and most likely need to install leaner carburetor jets. Leaner jets compensate for the excess fuel that is available when wet flow is put back into the air/fuel mix. Significant additional horsepower gains can be had with careful attention to cylinder-to-cylinder fuel distribution by allowing all cylinders to be set "just right"