The Viper PhatShaft is the perfect replacement turbo for towing and street use. The Viper PhatShaft can be purchased with a 12 or 14 turbine housing matched with a 68mm turbine. If the truck has heavier fueling upgrades such as aggressive fueling electronics, or large injectors then you will be better suited with 14cm housing. The benefit of the 14cm exhaust housing is lower Exhaust Gas Temperatures however, response will be slower in daily driving situations. The Viper PhatShaft is available in three different compressor sizes, 62mm, 63mm and 64mm. All three compressors have FMW, extended tip technology. The wategate is set at 40psi to prevent head gasket failure.. All Viper PhatShaft turbochargers are equipped with dual grooved bearings, 360 degree thrust bearing and an adjustable boost elbow.