This kit allows your engine to have full fueling to approximatey 4000RPM, which greatly improves the driving experience of a stock truck, for trucks with injectors and more, this kit is a must! We highly reccomend installing heavy duty 60lb valve springs if you plan on revving your engine to 3250RPM+.
The governor spring kit is designed to allow your pump to rev past factory settings without compromising pump safety.
4000RPM kits require use of heavy duty valve springs. We also highly recommend the use of billet valve retainers & keepers.