One of the first competition outings for the L88 Corvette was the 24 Hours of Le Mans in June of 1967. Driven by Bob Bondurant and Dick Guldstrand, the potent machine reached speeds of up to 171 mph but was eventually forced to retire with a broken engine. With the introduction of the C3 in 1968, true racing success came for the L88 Corvettes. In that year's SCCA A-Production class, a big-block Corvette would win eight races out of eleven attempts. The L88 Corvettes would remain successful for several more seasons, scoring outright wins on the American continent and also numerous class victories in international events.

For 1969 an even hotter RPO was added to the Corvette option book. Known as the ZL1, this included an all-aluminium version of the big block, which was also used in the popular Can-Am Challenge. Only around a dozen were built and reportedly just two were sold as the engine alone was just expensive as a complete small-block Corvette. Due to the high compression, the L88 could only run on 103 octane fuel, while the other competition components did not make it particularly suited to road. Experienced racing teams knew very well how to tweak the engine for full performance, like replacing the very restrictive exhaust headers. Later tests showed that the V8 was actually capable of producing in excess of 560 bhp.