The RPO Z06 package first offered on ’63 models included a 20 percent larger diameter front antiroll bar, a vacuum brake booster, a dual master cylinder, sintered-metallic brake linings within power-assisted Al-Fin drums cooled by front air scoops and vented backing plates, larger diameter shocks and springs nearly twice as stiff as standard.

These Corvettes came to be known as known as the “Big Tanks” because the package initially had a 36.5-gallon gas tank versus the standard 20-gallon for races such as Sebring and Daytona. At first, the package was only available on coupes because the oversized tank would not fit in the convertible.