The Gasket for the main Rail Goes over The top of the wings. Think about this for a sec When You put the motor together The oil pan is the Last thing to go on. Timing cover is already in place so is the rubber Gasket and the rubber gasket for the rear main
now
main
rail
gasket for the oil pan. So where is it sitting Over the tabs. So before you install the main rail gasket add a little RTV then lay the rail gaskets in place. Hope this helps.}[oooooo]