1970-78 and SVO Small Block. 5.700" Length. 3/4" Bearing. 3/4" Shaft. Special Severe Duty Pump. High Flow Pump. Cast Aluminum Finish. The Stage 4 Pumps incorporate the all new DRV-series 8 vane CNC machined 6061-T6 billet aluminum impellers. Developed by Stewart Components, these impellers flow up to 41 percent more water at twice the pressure than traditional designs... while consuming less horsepower. These are premium water pumps and carry the following features: Models with 3/4" ball/roller bearings offer five times the strength of standard bearings. Equal flow to left and right cylinder heads. High flow and pressure 356-T6 heat treated aluminum specially ribbed casting. Maximum flow close tolerance DRV-8 aluminum impeller. Zinc-plated rear cover and bolts. More flow than any pump available. More pressure than competing pumps. Less horsepower consumption. Precision ground 1/2" steel billet fan hub with dual bolt pattern for perfect pulley alignment. Fan hub set screw for positive positioning.