12 Valve 178/208 Camshaft Combo

What’s included:

• 178/208 Camshaft (fits 1989–2018 Cummins)
• Extreme Duty Pushrods (OEM–2,000+ HP)
• 155 Valve Springs
• Retainers and Locks
• Lifters/Tappets

If you’re looking for the quickest spool and widest RPM band of all our cams, this is it. It was initially designed for trucks that work hard and need instant torque in the low-RPM range. It was later found to greatly improve the spool-up of large single turbos, increase fuel economy, lower EGTs, maintain power at higher elevations, and retain significant horsepower and RPM potential.

It is also 49-state EPA compliant. If you think it is too small for your horsepower goals, think again. On our engine dyno, a 6.7L with a single S400 produced 1,100 HP with a stock head, 1,250 HP with a stock head and larger valves, and 1,588 HP at 4,500 RPM with a ported head.

Modification Required:

• For this camshaft to be considered “drop-in,” you will need no more than .020-inch piston protrusion and at least .055-inch valve-face depth with a standard head gasket. If your engine does not meet the minimum piston-to-valve clearance requirements, you can still use an oversized head gasket or cut valve reliefs.

Break-In:

To help prevent issues during break-in, follow these recommendations:

• Disconnect the fuel system and spin the engine with the starter until oil pressure is visible or oil is coming from the rocker arms on cylinder No. 6.
• Do not operate the starter for more than 10 seconds at a time.
• Once oil pressure has been verified, start the engine and allow it to run until it reaches operating temperature. Then shut the engine down.
• A hot re-torque is very important and will change the valve-lash settings. Always set the valve lash after completing the hot re-torque.
• Adjust the valves to .010-inch intake and .020-inch exhaust. You are then cleared to enjoy the added airflow.

Two or three times each year, we receive calls from customers who notice the valve lash becoming loose on the last three cylinders. This is typically caused by poor lubrication during the initial startup. In these cases, the camshaft can wear into the block due to the force of the tappets.

Assembly lubricant and verified oil pressure during the initial startup are extremely important. Do not allow this to happen to your engine.

———–Not for sale in the state of California———–

Approved oil is required.

Use a 15W-40 oil, or a 5W-40 oil in sub-zero conditions, with adequate zinc, phosphorus, and molybdenum. Thin or low-additive oils do not provide the shear strength required by a flat-tappet valvetrain.

Approved oils:

• Valvoline Full Synthetic 15W-40
• Valvoline Synthetic Blend 15W-40
• Valvoline All-Terrain 15W-40
• Schaeffer’s 15W-40
• Mobil Delvac Extreme 15W-40
• LIQUI MOLY Touring High Tech 15W-40
• Driven Racing Oil 15W-40
• Shell Rotella T6 Full Synthetic 15W-40
• Shell Rotella 15W-40