Ahh...he did the acid dipping too. Good read. He was the godfather of "tips"
As with most successful racers, Yunick was a master of the grey area straddling the rules. Perhaps his most famous exploit was his #13 1966 Chevrolet Chevelle, driven by Curtis Turner. The car was so much faster than the competition during testing that they were certain that cheating was involved; some sort of aerodynamic enhancement was strongly suspected, but the car's profile seemed to be entirely stock, as the rules required. It was eventually discovered that Yunick had lowered and modified the roof and windows and raised the floor (to lower the body) of the production car. Since then, NASCAR required each race car's roof, hood, and trunk to fit templates representing the production car's exact profile.
Another Yunick improvisation was getting around the regulations specifying a maximum size for the fuel tank, by using eleven foot (three meter) coils of 2-inch (5-centimeter) diameter tubing for the fuel line to add about 5 gallons (19 liters) to the car's fuel capacity. Once, NASCAR officials came up with a list of nine items for Yunick to fix before the car would be allowed on the track. The suspicious NASCAR officials had removed the tank for inspection. Yunick started the car with no gas tank and said "Better make it ten,"[2] and drove it back to the pits. He used a basketball in the fuel tank which could be inflated when the car's fuel capacity was checked and deflated for the race.
Yunick also used such innovations as offset chassis, raised floors, roof spoilers, nitrous oxide injection, and other modifications often within the letter of the rule-book, if not the spirit. "All those other guys were cheatin' 10 times worse than us," Yunick wrote in his autobiography, "so it was just self-defense." Yunick's success was also due to his expertise in the aerodynamics of racing cars.
Yunick also built a 1968 Camaro for Trans-Am racing. Although Yunick set several speed and endurance records with the car at Bonneville Speedway, with both a 302 cubic inch (~4942 cubic centimeter) and a 396 cubic inch (~6489 cubic centimeter) engine, it never won a race while Yunick owned it. It was later sold to Don Yenko, who did win several races. In typical Yunick fashion, the car, although superficially a stock Camaro, had acid-dipped body panels and thinner window glass to reduce weight, the front end of the body tilted downwards and the windshield laid back for aerodynamics, all four fenders widened, the front subframe Z'ed and the floorpan moved up to lower the car, and many other detailed modifications. The drip rails were even brought closer to the body for a tiny aerodynamic improvement. A connector to the engine oil system was extended into the car's interior, to allow the driver to add oil from a pressurized hose during pit stops. In order to allow the driver enough freedom of movement, the shoulder harness was modified to include a cable-ratchet mechanism from a military helicopter. In 1993, Vic Edelbrock, Jr. purchased and restored the car. Contrary to popular opinion, Yunick designed the first "safe wall" in the early 1960s using old tires between sheets of plywood but NASCAR did not adopt his idea. Also Yunick developed air jacks for stock cars in 1961 but NASCAR didn't deem them appropriate.
