SRT 12-VALVE

PUSHER INTAKES’ 11-SECOND, CUMMINS-POWERED SRT-10 REPLICA MEANS BUSINESS.

What do you do when the truck of your dreams falls short of your expectations? You build your own version.

Such was the case for Jacob Allenbaugh, owner of Pusher Intakes in Vero Beach, Florida. As a teenager, he developed an affinity for Dodge’s SRT-10, the ’04–’06 Ram half-ton graced with the 500 hp 8.3L V-10 plucked straight out of the Viper. However, as an adult—and with a background in mechanical engineering dictating a commonsensical lifestyle— Jacob could never justify owning one because of the dismal fuel economy the 10-cylinder sport truck offered. Hook onto a small trailer, and you can kiss goodbye any aspirations of seeing 10 mpg.

The Truck

Luckily, becoming an avid diesel enthusiast familiarized Jacob with the reality that big power and good fuel economy could go hand in hand, and he set about building his own SRT-10. All he needed were the right donor vehicles to get the project off the ground.

The first break came when he found an ’03 Ram 1500 sitting in a local shipyard. The 5.7L Hemi under the hood had eaten a valve; the owner was motivated to unload it; and its black exterior, clean interior, two-wheel-drive, standard cab shortbed configuration met all prerequisites. Needless to say, Jacob pounced on the deal.

The Powertrain

Shortly after hauling the ’03 home, Jacob got his hands on a friend’s ’94 Ram 3500. Aside from the 1-ton second-gen being powered by a P-pumped 12-valve, Jacob knew the simplistic 47RH it was attached to would make integrating the Cummins that much easier. As a bonus, the bone-stock engine had never been modified, which made the 223,000 miles it had accumulated anything but worrisome. Still, for good measure, Jacob pulled the head and dug into the bottom end to confirm that the well-caredfor Cummins was 100 percent ready to survive big horsepower. All told, the factory short-block would be subjected to 500 percent more horsepower than it had been in stock form.

Cam and Head Work

Upon reassembly, the OEM crank, connecting rods and pistons were retained, with a 194/215 cam from Max Spool Engineering getting the nod over the factory unit. For peace of mind at higher horsepower, the cam gear was also welded in place.

Virtually all other hard part upgrades revolved around the head. To keep the head gasket alive under big boost, it was O-ringed and secured to the block via ARP 425 studs. To eliminate valve float and creep under excessive boost and driver pressure, 110 ppi valve springs were installed. For improved airflow, Jacob treated the head to 0.100-inch larger valves and a full CNC port job. As for bolting the engine in place, virtually nothing was altered on the halfton’s frame in order to accommodate the Cummins. Furthermore, the fully boxed frame rails on the ’02-newer Ram 1500s are more than robust and almost invite this type of swap.

7x11s and a 440cc P7100

Waking up the Bosch P7100, Jacob treated it to a 4,000 rpm governor spring kit, .024 delivery valves and a healthy bump in timing. A few select additional tweaks brought the 160 hp pump to life even further, and while the 12mm P-pump was bolted to the

flow bench, it moved 440cc worth of fuel—not bad for a pump that once flowed fewer than 150 cc.

Accommodating the worked-over P7100 is a set of 7x0.011 Sac-style, 145-degree spraypattern injectors from Diesel Auto Power (these are comparable to 5x0.014 units). Consistent lowpressure fuel pressure is delivered to the P-pump, thanks to a 150 gph FASS system.

HX35 Over S475

The process of filling the 5.9L’s lungs begins with a Borgwarner S475, which serves as the atmospheric turbo in the truck’s compound arrangement. Matched with the factory Holset HX35 in what is known as Pusher Intakes’ Low-mount Compound Turbo system, the two chargers combine to produce a maximum of 68 psi of boost, according to Jacob. For superior exhaust flow, the hot-pipe between the HX35 and S475 features an integrated wastegate port. All that was required to make the budget-friendly ’94–’98 turbo arrangement work in the ’03 half-ton application was one tweak to an intercooler pipe and a slight reworking of the kit’s 5-inch downpipe.

Additional Airflow

Further airflow improvements come in the form of a Pusher Mega twin intake elbow. The dual inlet piece offers a 3.5-inch inlet (versus 3 inches stock) and connects to the second-gen intercooler out of the donor ’94 via a 3.5-inch cold-side intercooler tube. On top of the additional airflow from the compound turbo arrangement and 3.5-inch Mega twin intake system providing more overall horsepower, EGT barely touches 1,400 degrees through the quarter-mile. And, when boost is limited to 60 psi or under, no more than 1,250 degrees is observed.

Billet 47RH

Thanks to being highly supported in the diesel