If I am not mistaken, they are the same size. Keep in mind that 1947 is different and a single year drivetrain. I will double check the measurements on both 3 and 4 speed 1948+ transmission units tomorrow for you. Rich
1947.2 GMC 1/2T SWB panel 1947.2 GMC 1/2T long bed 1948 GMC 1/2T short bed