It's not my Gran National that's in question. Mine always has been and continues to be R-12 in all my and older sons older R-12 vehicles. '57 Studebaker P/U, (2) '70 SS 454 Chevelle, '71 S 454 Chevelle. '87 Regal Gran National, '82 Daytona 500 (Ferrari/Vette) ... Login to read more.