The Industrial Injection 4000 Governor Spring Kit is by far the best modification you will ever do to your 12 valve Cummins engine. The factory governor generally will slowly start to defuel the engine around 2300-2400 rpm and drastically decrease performance and pulling power. By simply installing the 4000 GSK into your P7100 injection pump you will allow the engine to fully fuel to 4000 rpm as well as greatly increasing throttle response and performance to help spool aftermarket turbos. We recommend our 150lbs springs with the use of this kit to prevent valve float above 3200 rpm.
