Bottom Line
High performance diesels
These wolves can ride with pride

Bruce Mallinson

In the December/January issue, I talked about the makeover of a 1998 extended-hood Peterbilt powered by a 12.7-liter Detroit diesel, owned by OOIDA member Marvin Veenstra, Belmont, MI.

This is the dark blue Pete that has the mural of the two white wolves on the top of the double bunk that pulls a reefer between Grand Rapids, MI, and Salt Lake City. The makeover is complete, and the results are shocking.

Let’s talk about what we did to this truck. With nearly 1 million miles on the odometer, many of the components needed attention. So we removed the radiator, engine, transmission and drive shaft from the chassis.

The drive shaft was balanced and straightened. New universal joints and carrier bearing were installed. A new Eaton clutch and resurfaced flywheel were added to harness the increased horsepower and torque. Now to keep the Detroit-powered wolves cool, a new high-tech radiator core was installed utilizing the original top and bottom tanks. The engine: ceramic- and Teflon-coated pistons, high-flow injectors, Pittsburgh Power Detroit computer, ceramic-coated head, high-flow turbo and all of the stock parts normally changed during a rebuild.

We also installed a Dyna-Flex exhaust system utilizing a straight-through resonator (California legal) and dual 7-inch straight stacks with baffles installed in the stacks. They have a 5-inch diameter hole straight through the center, so the entire exhaust system has no restriction and it’s quiet.

Now for the performance: Estimated horsepower is between 725 and 800, while producing 45 psi of turbo boost effortlessly. After we dyno test the truck, we will inform you of the exact horsepower.

Exhaust backpressure is 6 inches of water column, while the OEMs are allowing 60 inches of water column on new trucks. That is why we prefer straight-through flow on the exhaust systems — no backpressure and lower exhaust gas temperatures. This truck is quiet. The straight-through baffle system even removes the engine brake noise.

At Diesel Injection of Pittsburgh, we do not get to pull loaded trailers, so we have to judge the performance of the truck by bobtailing up the steep hills on Route 28. This 12.7-liter Detroit accelerates as though it were a 427-cubic-inch, 435-hp ’67 Corvette. It will put you back in the seat and keep you there until Marvin eases off the accelerator. It is a wonderfully addictive feeling and will stand up the hair on your arms. If you have never had the opportunity of driving a high performance diesel engine, you are missing one of the pleasures of living.

My booklet is now available for viewing or downloads on the World Wide Web. The address is If you would like a hard copy of our booklet, give Aimee a call at (724) 274-4080. There is a $9 charge for shipping and handling. Just call us with your Master Card, Visa, AMX or Discover card number and we will get one out to you. Or send us a check or money order to: Diesel Injection of Pittsburgh, 1403 Freeport Rd., Cheswick, PA 1502.