This is the trans of choice for high output engines up to 850HP. The 400Sx has a modified pump for higher operating pressure, 300M input shaft and re-broached forward clutch drum with larger spline contact area, 300M input clutch hub, semi metallic frictions, Kevlar lined front band with reinforced anchor points, extra direct clutch, 34 element intermediate sprag, improved design low reverse sprag, upgraded center support and customized valve body and governor with both automatic or semi automatic shift selection. The transmission is performance clearanced during the build including clutch packs and gear train as well as final endplay. Low drum is machined and a wider band used, low/second accumulator is modified for quicker band release. All external hardware is cad plated and the pan is a new, heavy steel part to resist leakage.