Hello Gentlemen, I have a 1986 Chev pickup truck with a 350 engine and Edelbrock heads. I can't seem to stop an oil leak from my valve cover on the passenger side. I replaced the gaskets three times with cork, Fel Pro, and Silicone. Each time I replaced them the oil leak would stop but gradually return until I could smell it burning. The oil leak seems to be at the back of the engine. It runs down the block after I park it overnight. The valve covers I had on it were from Edelbrock. I have since changed them after the last leak with a set of chrome valve covers with an even thicker cork gasket. It has now begun to leak again. Valve cover bolts still tight. Any suggestions?