John Paul began modifying Porsche machinery for IMSA in 1979, when he made his first 935 JLP from a 912 chassis (lighter than the 911). The fourth car in the series was the JLP4, built in 1982 with the intervention of the Fabcar, which made it a full-fledged prototype. Refined also from an aerodynamic point of view, the 935 JLP4 was now substantially different from the standard 935.