This 3600 rpm spring fits all VE Injection pumps on Dodges from 1989 to 1993. The spring will allow the injection pump to fuel all the way to 3600 rpm if you have enough fuel.
In other words a stock motor with no fueling mods may not spin all the way to 3600. Using this spring will make your truck much more driveable and will increase the amount of time your truck makes power.
No damage will occur to your motor at 3600 rpm, the Cummins 5.9 can be spun to that rpm without issues.