For use with all centerbolt style cylinder heads (LB4, L35, Vortec). RPM sheetmetal valve covers feature billet cnc 1/2″ thick 6061 aluminum rails, and hand formed 5052 aluminum bodies for an outstanding seal and appearance. Will clear any rocker arm combination.Valve covers come with 1.75″ oil fill cap. AN / npt bungs available at an additional cost. ¬†See options. ¬†May take 1-2 weeks for lead time. ¬†Call to confirm.