Stage 4 - For customers seeking the cutting edge in performance water pump technology, Stewart Stage 4 pumps are the ultimate water pump for any application! In addition to all of the quality features found in Stage 2 and 3 pumps, the Stage 4 pump utilizes the Stewart Components DRV-8 impeller. The key to the water pump's performance. This exclusive 8-vane impeller is fully CNC-machined from 6061-T6 billet aluminum. It's special design flows up to 41% more water (up to 160 GMP) at TWICE the pressure of traditional designs, all while consuming less than 3 horsepower at 4, 500 pump RPM. Recommended for the heaviest racing applications. All Stage 4 pumps feature:DRV-8 impellers machined from 6061-T6 aluminum billet More flow and pressure than any pump design available Less horsepower consumption per GPM Higher flow and pressure for better cooling A full one-year warranty. Models with 3/4" ball/roller bearings offer five times the strength of standard bearings. Billet steel fan hub, 1/2" thick with set screw for more positive positioning Exclusive Stewart 356-T6 heat treated aluminum casting Extra rigid cam stop with 3/8" adjustment screw (small block Chevrolet short castings) Extra material adjacent to block mounting bolts to allow drilling and taping of up to 1/2" NPT holes for installing external coolant lines to the center of the engine (small block and big block Chevrolet short castings) Precision ground fan hub for perfect pulley alignment. Equal flow to left and right cylinder heads. Precision impeller installed to exacting tolerance. Zinc plated rear cover bolt Stock external dimensions and hose location Special water/antifreeze compatible seal assembly.Pit Stop USA offers Stewart Stage 4 Aluminum Water Pump - Chevrolet SB - Short 43103 at low everyday prices. Be sure to check out all of our products from Stewart Components including Stewart Components Small Block Chevy Water Pumps.