For SBC Chevy Aluminum Crank Pulley Double 2 Groove For Short Water Pump SWP 350 400 SBC Chevy Aluminum Crank Pulley Double 2 Groove For Short Water Pump SWP 350 400 Polished aluminum crankshaft pulley for small block Chevy V8 engines. For use with "short" style water pumps. 2 V-belt grooves. 6.60" in diameter.