Melling 4.6L High Volume Oil Pump provides great oil flow for wider bearing clearances.Melling 4.6L DOHC High Volume Oil Pump has a larger inlet hole and hardened steel gears(about 25% longer) which provides additional oil flow for wider bearing clearances. The drive shaft and idler shaft have been extended into the cover providing extra support and eliminating any shaft deflection. The pressure relief spring plug is threaded for easy replacement, and some pumps have a heavy-duty driveshaft with a steel sleeve and extra spring where noted. Billet Steel Rotors (130,000 psi Tensile Strength). Hard Coat Anodized Pump Body. Magnesium Phosphate Coated Cover Plate. Engine Accepts 15/16″ Stock Pickup Tube Assembly.