754-0280 is a primary variable drive belt, engine pulley to vari-drive pulley. Part numbers 754-0280, 954-0280, 754-0280A, 954-0280A are the same part. Part 754-0370 is the secondary variable drive belt, vari-drive pulley to transmission pulley. Part 754-0370 is the same as 954-0370. Because of the difficulty and time involved changing just one belt we recommend changing both while you have every thing apart. Only takes another 15-20 minutes on most models. Please check you parts list to make sure that both these parts are right for your model.