Rear Differential Cover Heavy Duty 1963-77 and 1978-79
The "Rear Differential Cover" is a known weak area of the Corvette the rear cover supports the entire weight of the Corvette on hard launches and corners. The red heavy duty cover is 6 to 7 pounds heavier than the stock black cover compare them in the picture see how much thicker the edge of red casting is compared to the black rear cover. Note the picture of the two covers lying flat on the table you can easily see the heavier webbing ( u shaped area) of the red rear cover compared to the stock black rear cover. Covers are shipped as bare casting.