Can only clean up .125 under the seat....Not enough to even notice without a flow bench. Wissota, the sanctioning body, is really strict on the engine rules. As in many cases, there attempt at controlling the cost has led to higher costs in getting parts that will pass tech and still perform adequately. We're even giving some thought to running a Mopar, they are allowed 5 more cubic inches and the biggest advantage is the shaft rockers. With a Chevy or Ford engine we would have to run the stamped steel rockers.... I guess they have their reasons.... and they probably don't care if I agree or not. If we're going to play their game we have to play by their rules......