SMOKIN’ ADDICTION
TRIAL & ERROR IN A P-PUMPED 7.3L PULLING MACHINE
Ah, the rare gem that is the P-pumped 7.3L. It’s an engine combination born out of both necessity and loyalty. Folks that blaze this trail know it’s mandatory to scrap the HEUI injection system in order to be competitive, and their unshakable devotion to the 444-cubic-inch V8 keeps them from veering away from their Ford/power Stroke roots. Such was the case for Ben Burnworth and Nate Bailor, avid truck pullers who happen to own Unlimited Diesel Performance in Bremen, Ohio. After campaigning a Heui-fired 7.3L for years, the competition kept pulling away from their bull-nose Ford and both of them knew it was time for a change. “It was basically a 600hp truck at the time, and that was with compound S400s,” Bailor tells us. “It was doing good for a 7.3L, but wasn’t where we needed to be to run with the rest of the class.”
Trials & Tribulations
After hatching a plan to go mechanical, Bailor and Burnworth quickly learned that they were essentially on their own. Unlike with the Cummins camp, there is no set precedent as to what makes a mechanically injected 7.3L both competitive and dependable. As a result, a lot of trial and error lay ahead. Torched pistons, cracked heads, and turbo rule changes all literally threw wrenches into their plans at one point or another. In the end, it was all part of an extensive learning curve that led to the current parts combination, which has proven rock-solid reliable.
Block & Crank: The Only OE Parts
Aside from its retention of the factory block (which is filled with Hard Blok) and crankshaft (which is internally balanced), the
engine is a one-off work of art. A Hypermax bed plate eliminates the main cap walk the 7.3L is known for, and provides significant reinforcement for the crankcase. R&R Racing Products’ forgedsteel rods attach to 0.010-inch over, forged-aluminum FSR pistons from D&J Precision Machine, and a camshaft spec’d by Bob Holmes highlights the short-block’s key hard parts. A set of solid, re-cast cylinder heads from D&J Precision Machine represent the most exotic cast-iron 7.3L heads we’ve ever seen. They’re fireringed and graced with massive intake valves, Jesel roller rockers, 9/16-inch ARP studs, and they incorporate International-style, mechanical injectors.
The Inline Eight
Front and center in the lifter valley sits a worked-over, 13mm inline eight cylinder Bosch P7100 from Northeast Diesel Service. A billetaluminum front cover designed and machined by D&J Precision Machine accommodates the big P-pump, while a Waterman lift pump coupled to back of the R&R dry sump oil pump supplies
50psi worth of fuel pressure. Custom-bent injection lines branch out to International-based, dual-feed, billet-body injectors from Scheid Diesel.
A Properly Vetted Turbo
With eight cylinders and more than 440 cubic inches to feed, smooth-bore turbo rules have definitely muffled the power potential of this engine. But with the rules being what they are, Bailor and Burnworth had no choice but to exhaust every avenue to find the right charger. After spending countless hours on the engine dyno—which included the vetting of some of the best 3.0-inch smooth-bore turbos on the market—they settled on a unit from Columbus Diesel Supply. The Holset-based charger produces 50 psi of boost under peak load, but spins an incredible 130,000 rpm while doing it. When combined with a PT4000 Precision