Three different KS cars raced in the 1979 Japanese F3 Championship, they were the 06B, 06C and 06X, the O6C was Toyota powered, the 06X had a Honda and no engine is listed for the 06B. The best result was achieved by Osamu Nakako in the 06C with a third at Tsukuba but after this the car disappeared. The 06X only did one race and finished seventh at the opening round at Suzuka.