Mounting Kit Crusader Exhaust Elbow | Sierra 18-8515 Sierra Mounting Kit Crusader Exhaust Elbow | 18-8515 One hole exhaust elbow gasket with mounting bolts for Crusader log style manifolds. Sierra exhaust elbow mounting kit Fits many Crusader GM 305, 350, and 454 cu. In. marine engines For use with Sierra 18-1934, 18-1928, and 18-1918 elbows Replaces Crusader 96562 Replaces Osco 6562-MK