Billet Aluminum Water Pump Fan Pulley 240Z 260Z 280Z 280ZXNew billet aluminum water pump pulley for Datsun 240Z 260Z 280Z and 280ZX. Pulley is available with two different belt widths which we will call thinner and thicker, basically 3 8" wide or 1 2" wide belts. The idea is to get all of your pulleys to have matching belt widths for best performance. Thinner pulley groove= . 380" at the top of the "V". uses 3 8" or 10mm wide belts. Thicker pulley groove= . 440" at the top of the "V", uses up to 1 2" wide