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1978 Dodge Li’l Red Express - Cummins Express

A Muscle Truck with a Diesel Twist

Jason Sands
Jul 11, 2014
Photographers: Jason Sands
In the late ’70s, the fuel crunch was in full swing, and the performance car industry was at arguably its lowest point in history. Smog-laden big-block gas engines could barely crank out 200 hp, and even traditional performance vehicles such as the Camaro and the Mustang were much slower than previous models. This is how it came, then, that one of the quickest vehicles in the late ’70s was actually a Dodge truck, sold as a Li’l Red Express model. While the pickup was able to record quarter-mile times in the 15-second range in factory form, hot-rodders know there’s always room for improvement. Perhaps the quickest (and wildest) Red Express truck around is owned by Max Kirtley from Pearland, Texas.
The most noticeable change is in the title of the truck, which has been re-lettered to read: Cummins Express. You see, instead of the 5.9L police interceptor engine, the Cummins Express has a 1,200hp 5.9L Cummins 6BT, which has propelled the truck to a best quarter-mile of 10.0 at 130 mph, with a 1.43-second 60-foot time. Why a diesel? Well, in addition to shaving more than 5 seconds off the truck’s quarter-mile time, it also achieves upward of 25 mpg on highway stretches.
Photo 2/14   |   The interior of the Cummins Express is all business, with racing seats, harnesses, and a full rollcage. But, it’s also a street vehicle, which means carpet, roll-up windows, and a passenger seat.
Surprisingly, the truck was already fit with a Cummins when Max purchased it from George Cobb in 2009. Although the Dodge was a little rough, Max knew it had potential, and after a blown freeze plug sent it into the wall at the dragstrip, it was time for a full rebuild. The new and improved Cummins Express was built by Max and his buddies at Southern Sportz Racing and painted by Murillo’s Auto Body. Everything was painted, polished, or refurbished on the truck, including the wood in the bed.
With the truck’s looks taken care of, Max quickly moved on to the drivetrain. While the truck was plenty quick (mid 11s) when Max bought it, he was in the mood for more—much more. First, the engine was sent off to Manning Motorsports, where it was rebuilt and strengthened. The bottom end was balanced and blueprinted, and a stud girdle was added. The connecting rods were shot-peened, and marine-style, lowered-compression pistons were added. Manning Motorsports also supplied the valvetrain, with a Hamilton Cams cylinder head and ARP 625 studs rounding out the top end.
Having a solid foundation in place, Max turned his attention to making horsepower—a lot of it. For fuel, Farrell Diesel Service modified the stock Bosch P7100 pump with a quick-rate cam and 13mm plungers. Then, oversize injection lines were added that send fuel to a set of 5x22 injectors built by Infinite Performance. The airflow side of the performance equation is equally stout, with an 82mm High Tech Turbo turbocharger, custom HTT intercooler, Steed Speed exhaust manifold, and JGS wastegate all being thrown into the mix. If that wasn’t enough, a multi-stage nitrous oxide system is also incorporated for maximum performance.
Photo 6/14   |   An 82mm turbocharger from High Tech Turbo compresses air into the hungry 5.9L engine, while a spool valve from Infinite Performance helps get the big charger lit at the dragstrip.
While the reborn Cummins Express had classic lines and power, it still had to get down the track. This meant it needed a good transmission. To harness his red ride’s horsepower, Max turned to Calvin’s Auto Repair to build him a 47RH transmission that could handle the power, complete with billet shafts and a torque converter from Diesel Performance Converters. The final step in the performance equation was a suspension and braking system that would get Max’s Dodge down the track effectively and safely. Since the truck was already back-halved from the previous build, Max just needed to dial in things like the gear ratio, spring weights, and brakes to get those hard, wheels-up launches.
To our knowledge, there’s nothing out there quite like Max’s Cummins Express. With four-digit horsepower and a colorful history, Max’s Li’l Red Cummins Express just might be the ultimate muscle truck.
Photo 10/14   |   1978 Dodge Li L Red Express Front View
“The most noticeable change is in the title of the truck, which has been re-lettered to read: Cummins Express. You see, instead of the 5.9L police interceptor engine, the Cummins Express has a 1,200hp 5.9L Cummins 6BT, which has propelled the truck to a best quarter-mile of 10.0 at 130 mph, with a 1.43-second 60-foot time.”
Photo 11/14   |   1978 Dodge Li L Red Express Rear Wheel
Hard launches come courtesy of a 3.31-geared Dana 60 rear axle. The axle has been beefed up with a spool, and a dual-caliper pinion brake to help hold the massive Hoosier 32x14.5x15 slicks (shown here) at the starting line (and under boost).

Fast Facts
Year/Make/Model: 1978 Dodge Li’l Red Express
Owner: Max Kirtley
Hometown: Pearland, Texas
Engine: 5.9L Cummins I-6 built by Manning Motorsports with a Hamilton Cams 12-valve cylinder head
Fuel: Farrell Diesel Service 13mm injection pump, Infinite Performance 5x22 injectors with oversize lines, FASS and AirDog lift pumps
Air: High Tech Turbo 82mm turbocharger, HTT intercooler, three-stage nitrous system, Manning Motorsports intake
Transmission: 47RH with billet shafts and a manual valvebody, built by Calvin’s Auto Repair
Horsepower: 1,200 hp (est.)
Torque: 1,800 lb-ft (est.)
Tires: 225/70R15 Kumho Solus KR21 (front), 32x14.50x15 Hoosier drag slicks (rear)
Wheels: 15-inch Weld Pro Star
Suspension: Custom back-half with four-link and coil-overs (rear)
Axles: Dana 60 (rear) with 3.31 gears, a spool, and a pinion brake
Fun Fact: Others have noticed Max’s truck as well; it’s been on TV, in movies, and all over the Internet.

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