[John Rogers]

Rocker cover gaskets probably. They will come loose and the tops get pulled inside from the vacuum inside the engine at low RPMs and at high RPM will let oil blow out it it ends on that little ridge under the intake manifolds. My 2.8l does it and I am modifying a set of stock covers so this won't happen by MIG welding a strip of metal around the inside of the gasket area to hold the gasket in place. I'll take some picts and do an article for the site here when done. For the present use some good hi temp sealant, new gaskets and make sure the bale is tight. Good luck.