The SPD2 series of pumps are special SP-25A series pumps with through shafts. The through shafts have 9 tooth internal splines at the rear and the pump¿s rear cover has an integral SAE A 2 bolt mount pad. For double pump operation, a standard SAE "A" 2-Bolt splined shaft pump can be directly mounted on the rear on the SPD2. Typical performance of the pump is the same as indicated for the SP-25A series pump. -Prince Catalog Pages -Part List