Quick view Roush ROUSH 1996-2018 Ford Mustang Polished Billet Radiator Cap - 421258 Compare $59.99 Dress up the engine compartment of your Mustang with a ROUSH Billet Radiator Cap. The billet radiator cap is made from high quality billet aluminum for its appearance, corrosion resistance and strength to weight ratio. The radiator cap is manufactured in... Add to Cart Add to Cart