Power Driven 3K/4K Governor Springs — 1994–1998 5.9L 12v Cummins (P7100)

Governor springs are widely considered the best bang-for-buck first mod on a 12v Cummins. The stock P7100 injection pump is governed to cut fuel well before the engine reaches its potential — these springs raise that RPM ceiling, unlocking more power, sharper throttle response, and a noticeably different driving experience. One kit, one afternoon, immediate results.

Kit Includes

• Full set of 3K/4K governor springs
• Spring bases (retainers) included

3K or 4K — Which Do You Need?

• 3K (remove the center spring) — Raises the fuel cutoff to ~3,000 RPM. Safe for stock and mildly built engines. The right choice for most street and tow trucks. Better throttle response and power without pushing the engine beyond its limits.
• 4K (leave the center spring in) — Raises the fuel cutoff to ~4,000 RPM. More aggressive, best suited for built engines with supporting mods (upgraded valve springs, head studs, turbo). Not recommended for stock motors.

⚠️ We strongly recommend installing heavy-duty 60lb valve springs if you plan on revving to 3,250 RPM or higher. Without them, stock valve springs can float at higher RPM and cause engine damage.

Fits

• 1994–1998 Dodge Ram 2500 / 3500 5.9L 12v Cummins with P7100 injection pump

*May not work for all builds due to other engine/vehicle modifications.

Frequently Asked Questions

What do governor springs do on a 12-valve Cummins?

They raise the RPM limit of the mechanical P7100 injection pump, allowing the engine to rev higher and produce more power. It’s one of the most cost-effective performance modifications available for a 12-valve Cummins.

Will governor springs hurt my engine?

On a stock engine, 4K springs can accelerate wear. 3K springs are generally safe for stock or mildly built motors. We strongly recommend installing heavy-duty 60lb valve springs if you plan on revving to 3,250 RPM or higher.

Do I need any special tools?

Basic hand tools and mechanical knowledge are sufficient. Installation is straightforward — watch the install video below. Our optional Governor Spring Adjustment Tool makes the job easier if you plan to do it more than once.