Replace your rear end cover with a heavy-duty unit, designed for everyday driving. Heavy Duty Differential Cover, for 1963-1977 Corvettes with 2 1/4" wide rear spring, cover is beefed up in the weak area's of the original. Tougher than factory, these cast iron 1963-1977 Corvette Rear Differential Covers boast reinforced spring mount tabs and a gusseted spring pad surface. Highly recommended to withstand the stress of high performance Corvette driving.