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2003 Chevy Silverado 2500HD - Nasty Girl

Introducing The World's Most Powerful Duramax

Jason Sands
Oct 1, 2007
Photographers: Jason Sands
Photo 2/2   |   2003 Chevy Silverado 2500hd nasty Girl Truck
Welcome to the saga of Nasty Girl, one of the most talked-about trucks of the year-and the first Duramax to make more than 1,000 rear-wheel horsepower (rwhp) on a chassis dyno. When the truck put up the original number (without nitrous, mind you), there was talk of power spikes, shifts on the dyno, and many other factors that could have skewed the readings. The big news was the repeat: more than 1,000 rwhp on a different occasion, on a different dyno, and again, without nitrous.
The truck itself is an '03 Chevy Silverado 2500HD owned by Keith Bachler of Medicine Hat, Alberta, Canada. It's powered by an LB7 Duramax engine that has a stock block and crank, but that's about it. Every other part on the engine has been massaged, modified, or replaced. The crank swings a set of Crower rods and a set of custom 13.5:1 coated LBZ pistons from SoCal Diesel. The heads have been CNC'd and ported by SoCal and were also treated to a prototype rev kit from Exergy Engineering. The cam is also from SoCal Diesel and was ground to custom specifications for the engine's compression and turbo setup.
Fuel is handled by a beltdriven lift pump that feeds custom-tweaked dual CP3 injection pumps. High-pressure #2 diesel then flows to a set of balanced and Extrude Honed injectors by Exergy Engineering. One of the big achievements with this engine is the turbos, which are a big part of why this engine rocks the dyno like it does. The turbos in question are a set of Maximized Performance compound twins, and little is known about them other than they combine to make up to 80 psi of boost pressure. A set of headers from Midwest Diesel feeds these twins, while the air from the compressor side goes through a Banks Technicooler before it reaches the built engine. Exhaust is handled by a custom 5-inch downpipe leading into dual 5-inch pipes that exit out the back into 6-inch chrome tips.
A stock Allison transmission would melt behind this kind of power, so Merchant Automotive built one that would live behind Nasty Girl, with billet input and output shafts from Intelligent Engineering and a converter from Inglewood Transmissions.
As impressive as Keith's truck is on the dyno, it was actually built for quick times at the dragstrip, so the rest of the truck has to be up to spec. To make sure all the power goes toward propelling the truck, rather than up in smoke, a set of CalTracs lift bars were installed on the Silverado's rearend. The front suspension was beefed up with a pair of Cognito braces, tie-rod sleeves, and a Super Diesel centerlink to prevent breakage during hard, four-wheel-drive launches. In addition to all the beefed-up suspension parts, the truck is also NHRA legal for the strip thanks to a custom rollcage, trans blanket, and driveshaft loops. Keith isn't taking any chances on his 10-second goal, so the truck will be fitted with a set of 325/45-17 M&H Racemasters when his 7,200-pound truck hits the track.
After he gets his timeslips, will Keith be done with the truck? Of course not. When building something this specialized, it often takes a lot of tuning. At the Merchant Automotive event in Holland, Michigan, the truck made 1,036 rwhp despite making only 55 pounds of boost. With some more custom tuning by Ridge Runner Diesel and 25 psi left to play with, Keith feels he has 1,200 rwhp in his existing combination. After that, the truck will be on to its next life as Keith's daily driver.
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