Plumes of smoke could be seen on the horizon from Highway 3. At the Yellowstone Dragstrip just west of Acton, diesel machines gathered to run the quarter-mile.
Big Sky Truck Fest rolled through this weekend as part of the National Hot Rod Diesel Association's national drag race and sled pull series. It was the last event before the World Finals, which will be held in Texas on Sept. 30.
Early Saturday afternoon, NHRDA Race Director J.J. Murray worked from the announcer's building as vehicles from nine traveling pro classes went through qualifying runs.
"They range from your basic street truck to your pro semi trucks," he said.
All of the drivers and pit teams sought a piece of the $40,000 prize pot for the weekend event, which included drag racing, sled pulls and best-of-show.
Jarid Vollmer piloted the custom 1941 Willys coupe for the afternoon's qualifying run. He pushed through a 7.9-second quarter-mile at 172 miles per hour for the pro stock class.
The car was part of the G & J Diesel Performance fleet. A Billings company, G & J has helped to sponsor the Yellowstone Dragstrip stop in the NHRDA series for 10 years.
Brad Makinen, owner of G & J, said that the Willys can do better, but the 7.9-second run was nothing to scoff at.
The low, sleek Willys is powered by a 1,300-horsepower Duramax diesel with twin turbos, Makinen said. The team had a custom chassis made for the vehicle to handle the high-torque power of the diesel motor.
While waiting for the car's engine to cool before the next run, Makinen and his team prepped other gear in front of a large G & J trailer.
He said that a tight group of friends formed among the teams that return to the diesel race circuit year after year.
"They're all like family," he said. "They're going through my bus, taking tools. We all share."
And what about all that black smoke? The emissions are due to an excess of fuel running through the engine — a practice colloquially known as "rolling coal."
The excess material is ejected as black clouds of soot. The Environmental Protection Agency deems it a violation of the Clean Air Act to tamper with computerized fuel injection, but rolling coal has become a hallmark of modified diesel trucks.
Makinen said that dumping more fuel through the system helps the motor run cooler, and it pushes the two turbo units. And, he added, it pleases the gallery.
"We can run these clean, but the crowd doesn't like it," he said.