Ok. I'm telling why. In case someone else has the same issue. The 408 I have is magnum based. They only put magnums in trucks. No cars. So all the sumps are rear. So you have to use a L.A. pan. Magnum pans use a one piece gasket. But you cannot use magnum gasket with L.A. pan. You have to use a 4 piece gasket for LA engines. Or they leak under pressure. There you have it.