PDI Big Boss Intake Manifold for Cummins ISX CM870 (2003–2007)

Part Number: 3682657
Engine Compatibility: Cummins ISX15 CM870 (2003–2007)
Warranty: 1-Year Limited Mileage Warranty

Unlock Better Airflow, Cooler Temps & More Power

If you’re searching for how to get more horsepower from your Cummins ISX CM870 or looking for an intake manifold upgrade for ISX, the PDI Big Boss Intake Manifold delivers proven performance.

Factory intake manifolds are engineered with restrictions that prioritize emissions compliance over performance. This typically results in reduced clean air flow and increased exhaust gas recirculation (EGR). Over time, this can lead to hotter intake temps, inefficient combustion, and power loss.

The Big Boss Intake Manifold is designed to increase clean air flow by up to 15% while fitting directly into the OEM location using factory hardware. By eliminating the restrictive “necked down” section and replacing it with a larger, open port design, this upgrade improves both air delivery and combustion efficiency.

Key Benefits

• Up to 15% more clean air flow into the engine
• Reduces intake air temperatures for more efficient combustion
• Gain 15–20 horsepower on average
• Direct bolt-on fit using factory hardware and position
• Improved fuel economy and throttle response
• Engineered and Made in the USA

Emissions Notice

NOT LEGAL FOR SALE OR USE IN CALIFORNIA or any other state that follows CARB emissions standards.

OEM Cross Reference

OEM Reference Number: 3682657

Installation

Designed for easy installation, this manifold mounts directly into the factory position and reuses OEM mounting hardware—no custom fabrication required.

Frequently Asked Questions (FAQs)

What gains can I expect from the PDI Big Boss Intake Manifold?

Most users report an increase of 15–20 horsepower, lower intake temps, and improved fuel efficiency thanks to cleaner, denser air entering the combustion chamber.

Is this intake manifold legal for use in all 50 states?

No. This product is not legal for sale or use in California or any state that adopts California emissions standards (CARB-compliant).

Is the installation difficult?

No. It is a direct bolt-on upgrade that uses factory mounting hardware and position. No modification or special tools required.

What engines is this compatible with?

It fits all Cummins ISX15 CM870 engines manufactured between 2003 and 2007.

Why does the stock manifold reduce performance?

OEM intake manifolds restrict clean airflow to increase EGR flow for emissions. This sacrifices engine performance and combustion efficiency. The Big Boss intake opens up the flow path, reducing intake temps and improving engine output.

Is this product made in the USA?

Yes, like all PDI products, this intake manifold is proudly Made in the USA.