Stewart Stage 4 pumps are the cutting edge in performance water pump technology. The Stage 4 pump utilizes the Stewart Components DRV-8 impeller. This exclusive 8 vane impeller is fully CNC machined from 6061-T6 billet aluminum. It's special design flows up to 160 GPM, while consuming less than 3 horsepower at 4, 500 pump RPM. Stewart Stage 4 pumps are the ULTIMATE water pump for any application!Note: All Stage 4 high flow water pumps require a Stewart/Robert Shaw high performance thermostat for proper performance. Chevrolet Small Block - Short 1955-68 Passenger Cars 1955-72 Light Trucks 5. 625" length 3/4" Bearing 3/4" Shaft Special Severe Duty Pump Adjustable mounting holes High Flow Pump Cast Aluminum FinishThese 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 Extra rigid cam stop with 3/8" adjustment screw for small block models Two 1/2" NPT auxiliary inlets Extra material on small block Chevrolet models for installing external lines to center of the cylinder heads More flow than any pump available More pressure than competing pumps Less horsepower consumption Precision ground " steel billet fan hub with dual bolt pattern for perfect pulley alignment Fan hub set screw for positive positioningPit Stop USA offers Stewart Stage 4 Aluminum Water Pump - Chevrolet SB - Short 42200 at low everyday prices. Be sure to check out all of our products from Stewart Components including Stewart Components Small Block Chevy Water Pumps.