Polished aluminum billet 6 groove serpentine Alternator, crank and water pump pulley set. These are for the Ford mustang GT 1996-1998 AND 1996-1999 Cobra 4.6L engine. long water pump the long style water pump, 1 7/8". wide, as measured from the pulley face. The pulleys are CNC-machined from the lightest, most durable materials possible; 6061-T6 aluminum billet and polished to a near mirror finish.