Boosting Performance: Intake Upgrade for Stock to Not’s 12-Valve Cummins

Tucker Harris . November 11, 2024 . Diesel World

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GIVING ‘STOCK TO NOT’ AN INTAKE HORN UPGRADE

Words by Tucker Harris Instructions Condensed from Pusher Intakes

Got a 12-valve Cummins under the hood? Then you probably know that the airflow inside these engines isn’t exactly winning any efficiency awards. But don’t worry—our “Stock to Not” project still has some tricks up its sleeve for improving street performance … or does it?

Enter Pusher Intakes from sunny South Florida. Since hitting the diesel scene in 2008 with its top-notch 12-valve parts, the company been a game-changer for diesel enthusiasts everywhere.

Today, we have “Stock to Not,” our trusty project truck, parked in the driveway, ready for an upgrade. Our mission: to swap out our freshly powder coated parts (stay tuned for more on those next month) and install this gorgeous Pusher twin ram intake kit. The kit comes with the intake, a 3.5-inch cold side pipe and plenum, plus all the T-clamps and gaskets you need for ‘94-’98 12-valves. This upgrade promises better boost displacement in the head and cooler intake air temps, giving us a cooler run down the track.

A quick note: These instructions assume our truck already has a grid heater delete, OEM filter housing delete, and a modified fuel return line. So, we’ve condensed the original instructions a bit. Ready? Let’s get to it!

**Step 1:** When gearing up for any equipment upgrade or retrofit, your first mission is clear: take plenty of pictures of the original setup from every angle you can think of. Trust us, your future self will thank you. And if you ever need assistance or customer service from Pusher, those photos from step one will be your golden ticket.

**Step 2:** Remove the five bolts that secure the factory intake manifold to the engine along with the dipstick bolt and set them aside. You will reuse some later.

**Step 3:** Loosen the factory T-bolt clamps that secure the charge tube to the intake manifold and remove the intake manifold.

**Step 4:** Remove the connector to the Intake Air Temperature (IAT) sensor at the back of the plenum plate.

**Step 5:** Remove all fuel lines from the injection pump and injectors. Do not remove/separate the mid-line gusset support brackets from the fuel lines at this time.

**Step 6:** Remove the remaining hardware connecting the stock plenum plate to the head.

**Step 7:** Remove the factory plenum plate and transfer the IAT sensor to the Pusher Plenum Plate using Teflon tape or paste on its threads.

**Step 8:** Clean all remaining gasket material of the cylinder head that once sealed the factory plenum plate. It is highly recommended to have a vacuum handy to remove any debris that fall into the plenum. Leaving debris behind can cause severe engine damage.

**Step 9:** Install the new plenum gasket and plenum plate. The angled and threaded tab on the new plenum plate is where the fuel filter bracket will mount at the rear driver side.

**Step 10:** Slide one of the supplied T-bolt clamps onto the intercooler then loosely install the supplied 3.5-inch 45-degree coupler onto the outlet of the intercooler. Pointing this clamp’s threaded portion down and placing it on the passenger side of the coupler to be the easiest way to tighten it later (first picture below). This coupler must be started straight on, all at once. Trying to start one side first rarely works. Do not tighten the clamp.

**Step 11:** Slide the supplied 3.5-inch charge tube into the outlet side of the 45-degree boot and orient its clamp as shown for optimum accessibility.

**Step 12:** Reinstall the injector lines (rear cluster first is easier).

**Step 13:** Place the supplied intake manifold gaskets where the intake manifold will mount to the plenum plate. These gaskets are slightly rectangular so make sure they are clocked properly. Also make sure the plenum plate gasket is aligned with the bolt holes and not blocking the bolts from being threaded in once the intake manifold is installed.

**Step 14:** Insert the intake manifold inlet into the coupler on the charge tube, and then align its flanges with the plenum plate. Use the eight supplied Cummins-style bolts and stainless washers to loosely secure the intake manifold to the plenum plate. Check the alignment of everything then tighten all of the hardware securing the plenum plate and intake manifold to the cylinder head. The supplied injector line bracket will mount on top of the rear manifold flange’s front passenger-side bolt hole.

**Step 15:** Secure the dipstick to the threaded boss on the intake manifold with the supplied M8x8mm bolt.

**Step 16:** Check the alignment of each silicone coupler then tighten all clamps.

**Step 17:** Plug in any remaining electrical sensors and check all hardware again. Connect any boost pressure sensors to the manifold ports or install the provided plugs.

**Step 18:** It may take your truck 30-60 seconds to start the first time as it purges all the fuel lines with fuel. Pumping the plunger on your factory fuel pump can shorten this time. You can also crack open one or two injector lines while initially starting the vehicle.

Step 19: Enjoy your upgraded ride and please let us know if you have any questions or feedback – thank you for your business!

ABOUT PUSHER

Pusher Intakes is a small, family-owned business based in southeastern Florida. All of its parts are designed in-house and always manufactured in the USA. The team there has invested an incredible amount of time and resources into making all of their products the best they can be and continue to look for ways to make them even better. For more information, call 772-212-9290 or visit PusherIntakes.com.