A different bracket must be used if your alternator is mounted over the exhaust manifold towards the outside of the head. Due to alternator belt interference problem with base and adjusting arm. Short water pump applications may require a 3 groove crank pulley.. This is for an OE style Saginaw power steering pump with a new reservoir, cap, chrome hardware and new dipstick. Early Chevy style 1965-79 pump with threaded and 5/8 keyed shaft.