A Father & Son-Built, Drag Racing Duramax

• July 26, 2021
• Story By
  Mike McGlothlin

It doesn’t get much better than a father and son team in motorsports. The long nights in the shop, overcoming setbacks at the track and the pride that comes from racing a vehicle you built with your own hands is even more meaningful when it’s shared with blood. Already having been inflicted with the diesel performance bug a few years back, Paul Edwards noticed his son, Collin, getting the itch as he approached his sixteenth birthday. To properly feed the addiction, the two decided to find a reasonably priced, lightweight 4x4 diesel truck and go drag racing—which led to the purchase of this ’05 standard cab Chevrolet Silverado ¾-ton.

Encouraged by the truck’s initial 8.0-second eighth-mile elapsed times, Paul and Collin got busy ordering parts and went to work. Wrenching out of a rented 30x30-foot garage and learning as they went, the truck was lightened, the Duramax under the hood was treated to a major increase in fueling and one of the largest S400 frame turbochargers on the market was mounted in the valley. By April, they found themselves back at the track ready to make a few more runs through the '660. The truck responded by going 7.09 out of the gate on fuel alone—which not only got them thinking about running the 6.70 Index class but eventually competing in the 5.90 category. This is their story.

Lightweight Yet 4x4—Perfect For Diesel Drag Racing

Believe it or not, Paul and Collin Edwards’ ’05 Silverado 2500 HD has more than 417,000 miles on the clock. The LLY code Duramax V-8 has accumulated 217,000 miles since the truck’s original engine was replaced at the 200,000 mile mark. Aside from the added heft of four-wheel drive (namely the transfer case, front differential and drive shaft) the classic body GM’s were one of the lightest ¾-ton and 1-ton diesel pickups ever produced. After a full winter of shedding weight and even ditching the entire A/C system, Collin tells us the Bow Tie now registers just 5,500 pounds when it rolls across the scales.

The Big Stage

A year and a half in the making, the Edwards brought their Silverado to the biggest stage it’s seen yet at the ODSS Outlaw Diesel Revenge event in Indianapolis. There, a month after finding out the truck would likely go high 6’s in the eighth-mile—but also knowing its lack of a roll cage would limit their ability to see what the truck was truly capable of—Collin’s focus behind the wheel was catered more around consistency than speed. Running the ET Bracket class that weekend (in a field of 42 trucks, no less), Collin went the deepest he’s ever gone in eliminations.

Untouched 6.6L

Beneath the 5-inch intake tube, the massive turbo in the valley and the 3-inch intercooler piping, you’ll find an LLY Duramax with a bone-stock long-block—not even the head bolts have been changed out for studs. While some might consider sitting at this power level (roughly 700rwhp) on a stock set of connecting rods to be a major no-no, the big single turbo helps limit the amount of drive pressure the engine sees, which often helps the factory long-block live in high-horsepower, race-only applications. A major source of the truck’s power comes from a set of 300-percent over injectors and a 14mm CP3 from Exergy Performance.

The Godfather

Near-endless horsepower potential can be found in the turbocharger Paul and Collin have opted to run. Built by Stainless Diesel and called its S485 “Godfather” charger, it utilizes one of the company’s billet, 5-blade compressor wheels. The “85” represents the compressor wheel’s 85mm inducer diameter. The T-6 flange Godfather is driven efficiently thanks to a set of PPE up-pipes, which feed an exhaust collector and pedestal built by ProFab Performance. This same turbo has been dyno-proven to support nearly 1,900rwhp (achieved on this truck).

A Transmission That Can Hack It

Working with and seeking advice from industry leaders definitely has its perks. Case in point, the Allison transmission in the Edwards’ Silverado came out of Dirty Hooker Diesel’s Pro Street truck. Originally assembled to handle the abuse of an engine turning out more than 2,000 hp, the DHD Allison sports billet internals and a J model torque converter from Goerend Transmission. Its 3,200-rpm stall speed helps bring the big S485 turbo to life during staging and Collin currently foot brakes the truck into that rpm range before launching.

Guidance From The Best In The Business

After receiving invaluable advice from diesel drag racing’s only driver to ever turn in a 3-second eighth-mile, Larson Miller, Collin proceeded to cut his best reaction time to date. Collin and his father have both commented on how helpful other drivers and race teams have been in offering tips, tricks and encouragement each time they make it to the track. Prior to the new personal best reaction time, Stainless Diesel’s Johnny Gilbert offered a few secrets as well, namely on air pressure and overall track setup.

ET Bracket, 6.70 Index And 5.90 Index Plans

While Paul and Collin await their turn at the fab shop to outfit the truck with a cage, they’ve decided to run a conservative tune-up and chase points in the ODSS ET Bracket class for now. They’ve yet to miss a race this season and as a result are currently sitting fourth overall in points. Once the cage is in and Collin continues to accumulate seat-time, they plan to turn things up enough to run the 6.70 Index class—and may even pull out all the stops and bump up to 5.90 Index down the road. After all, the truck is already light and could be made a featherweight if they decide to go to a tube chassis, ditch the leaf springs and install fiberglass body parts…