sometimes an engine will need a modification to go with another modification. It is always best to locate a problem and correct it rather than applying a band aid. for instance lets say you street drive the car more than you race it and suddenly it develops a rear seal leakage problem.......(and that's a big problem) you can contribute the failure of that rear seal to the fact that you eliminated the vacume that was engineered to keep that rear seal from leaking......I rest my case :grommit: