BESTgasket is the world's premier manufacturer of gaskets for vintage and classic American cars and trucks. BEST Gasket complete/full gasket set for 1957-1958 Oldsmobile models and 1957-1959 GMC models with the 371ci (370ci) V-8 engine; including J-2 engines. P/N RS512G. BEST Gasket is the leading name in sealing performance in the restoration industry.