Hamilton Cams 07-cc-24v19+ Flat Tappet Conversion (2019-2024 6.7L Cummins)

Fitment

Built for 2019-2024 Ram 2500 and 3500 pickups with the 6.7L Cummins. Hamilton Cams states the kit fits and is emission certified for all 2019-2024 Ram 2500 and 3500 diesels not in California. Hamilton does not do business in California, so the kit is not offered for California trucks. The lifter design it replaces is shared by the standard-output and high-output engines, and the kit is listed for both the 2500 and the 3500.

It is not listed for the 2025 and newer 6.7L. That engine has a redesigned block and head, and 2019-2024 engine parts should not be assumed to fit it. Our catalog tag reads 2019-current, but the kit's listed range is 2019-2024, so verify fitment by VIN. If your engine block or cylinder head has been surfaced, call before ordering so the kit can be verified for proper fitment.

Why this part

The hydraulic roller lifters in the 2019-2024 6.7L are the known weak spot of this engine. They have no needle bearings, run tight tolerances with undersized oil passages, and use a pressed steel alignment dowel that can back out. When a roller collapses or seizes, it gouges the camshaft and seeds the oil with metal. Watch for a typewriter-like tick on cold start that does not fade, metal in the oil, or a misfire. Some engines have shown it within the first 10,000 miles.

Putting new factory-style lifters back in leaves you with the same design. This kit changes the design instead. Hamilton Cams calls the factory hydraulic roller lifters and camshaft problematic and converts the engine to a flat tappet setup: a forged cam, DLC-coated tappets, stiffer pushrods and adjustable rockers with DLC-coated trunnions. Valve lash is set at the adjustable rockers, and the kit is certified for street use in 49 states.

What you get

Hamilton Cams lists the kit contents as:

• 178/208 Forged camshaft
• DLC coated steel tappets
• Upgraded pushrods
• Adjustable rocker arms with DLC coated trunnions

Forged steel camshaft

• Tighter Grain Structure: Hamilton's 178-208 steel cams are forged, not cut from bar stock, resulting in a more dense, more uniform grain structure.
• Enhanced Longevity: A natural “halo” in grain structure forms on the exterior of the cam during forging, adding a layer of strength for extended service life.

DLC-coated tappets

• Gas Carburized & Polished: Each tappet goes through a hardening process that gives it the hardness to act as a very stable base metal for the DLC coating.
• Diamond-Like Carbon (DLC) Coating: A very hard surface finish that reduces friction and wear. The installation notes below cover the oil, lash and rpm limits that protect it.

Heavy-duty pushrods

• 3500+ lbs Buckling Force: Compared to around 1800 lbs for OEM pushrods, these reduce deflection at high cylinder pressures.
• Consistent Valve Timing: With less flex, the valvetrain stays in sync under hard use.

Upgraded rocker arms

• Casting: Built to handle intense stress and heat cycles.
• Gas Carburized Ball & Foot: Reduces friction and wear for longer service intervals.
• DLC-Coated Trunnion: Minimizes galling, a common issue with OEM trunnions, and lowers overall friction in the valvetrain.

Specifications

• Part number: 07-cc-24v19+
• Camshaft: 178/208, forged steel
• Tappets: DLC-coated steel, gas carburized and polished
• Pushrods: 3500+ lbs buckling force (OEM around 1800 lbs)
• Rocker arms: adjustable, gas carburized ball and foot, DLC-coated trunnion
• Intake Valve Lash: 0.010″
• Exhaust Valve Lash: 0.020″
• Certification: 49-state, SEMA-certified for street use; not for California

Installation notes

Set lash to Hamilton's spec: intake 0.010″, exhaust 0.020″. Lash that is too loose increases the impact when the lash goes to solid and can damage the tappets or the coating, so make sure your lash is correct.

Oil matters more with flat tappets than with rollers. The factory oil for the stock 2019-2024 engine is 10W-30 or 5W-40 CK-4. With this kit in the engine, Hamilton Cams recommends:

• Valvoline 15W-40 Premium Blue
• Schaeffer 700 Series 15W-40

Here is why. Thin viscosity oils do not provide the hydrodynamic wedge a flat tappet needs, and oils low in zinc, phosphorus and molybdenum do not carry the additive package it needs. DLC lowers friction and extends part life, but incorrect oil, incorrect lash or valve float can damage it. High rpm amplifies the impact of the camshaft on the tappet, and Hamilton discourages high spring pressures and high rpm for longevity. When viscosity is too low, lash is too loose or rpm is too high, the oil film is not strong enough to keep the tappet and cam apart. The DLC then degrades into graphite and starts to decompose and delaminate.

Plan this as cam-out engine work. On this engine, changing lifters in the frame means holding the lifters up with magnets while the cam is pulled and working through a trough in the cam tunnel. If a lifter drops, the oil pan has to come off. If you would rather not take that on, call the shop.

About Hamilton Cams

Hamilton Cams builds valvetrain and top-end parts for the 5.9L and 6.7L Cummins out of Lampasas, Texas. The line is built around two cam profiles, the milder 178/208 and the bigger 188/220, sold bare or as complete combos for 12-valve and 24-valve engines, along with head gaskets, gasket kits and forged valve bridges. Hamilton says its cams are backed by decades of research, thousands of dyno tests and millions of real-world miles.

Frequently asked questions

Will this kit fit my 2025 Ram 2500 or 3500?

It is not listed for 2025 trucks. The kit is listed for 2019-2024 Ram 2500 and 3500 diesels. The 2025 and newer 6.7L has a redesigned block and head, and 2019-2024 engine parts should not be assumed to fit it.

Can I keep running 10W-30 after the conversion?

Hamilton Cams recommends Valvoline 15W-40 Premium Blue or Schaeffer 700 Series 15W-40 with this kit. Thin oils do not hold the film a flat tappet needs, and low-zinc oils lack the additives. The wrong oil can break down the DLC coating on the tappets.

Is the kit legal for street use?

Hamilton Cams states it is 49-state certified, SEMA-certified for street use in 49 states, and emission certified for 2019-2024 Ram 2500 and 3500 diesels outside California. Hamilton does not sell it for California trucks.

Questions on fitment? Call the shop at the number in the header. We install everything we sell.