1,000HP L5P It happened. Wehrli Custom Fabrication and All In Truck Performance have collaborated on a 1,000-rwhp L5P Duramax build. A WCFab S400 single turbo install kit, fitted with a 73mm G42-1200 Garrett (73/85/1.01) charger, Exergy 100-percent over L5P injectors, a custom Exergy 12mm stroker CP3, and a 165-gph lift pump system highlight its power-making recipe. A built Allison backs up the late-model Chevrolet’s 1,007 hp and 1,522 lb-ft of torque. But how is the factory rotating assembly holding up with that much power on tap? So far so good on what we presume is a bone-stock long block!