I just purchased a 1999 fxdx with a 124" s&s conversion as a project as it has been damaged. The bottom of engine case has oil leak at seam. Case has been hit and cracked and repaired with epoxy at one time. I intend to dismantle engine and see if case can be fixed properly. My question is, can the case halves be milled at the seam if need be? The leak is very small and if any milling is called for would be a small amount. If ok to mill what would be max amount? Thank you