I built a mild 355ci and I have changed the oil pan seal 3 times and it still finds some place to push oil out. If I run it easy (not over 5000rpm) then its fine but if i push it to 7500 or even 7000 it starts to leak and when idiling will slowly stop. I have the one peace thick Mister Gasket gasket and have put form-a-gasket on both sides and let it dry for days untile I start it and yet still leaks at Hi rpm's. I have a 30% more flow oil pump, and have a brether tube on one valve cover the other one is pluged with a cap. Do I need a windage tray, or is it building crankcase pressure. anything will help thanxs.