Patrick So you want to use the R-12 'cause that is what it was designed for. Do you also use straight weight oil for the engine? The point is what was availiable when "it" was designed. And your tires are ..... Rodger & Gabby Colo Spgs '47 De Soto Custom w/Fluid Drive & passenger door mounted swamp cooler '63 Le Baron w/F-Sweep trunk lid & std A/C '66 Le Baron w/dual A/C & reverbed AM/FM