Chevrolet Small Block short style water pump. 5.625 inch hub height, 3/4 inch Bearing, 3/4 inch Shaft, Cast Aluminum Finish. The Stage 3 has been Stewart's most popular pump for over 10 years. They have the following features: Equal flow to left and right cylinder heads. Exclusive 356-T6 heat treated aluminum specially ribbed casting. Zinc-plated rear cover and bolts. Two 1/2 inch NPT auxiliary inlets. High flow impleller. Precision ground 1/2 inch steel billet fan hub with dual bolt pattern for perfect pulley alignment. Fan hub set screw for positive positioning. Recommended for high RPM and any racing applications.