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Oct 18, 2011
Lakeland, FL

Stretch Run
Opening up a GT350 exhaust with ARH long-tube headers yields big gains
By Steve Turner
Photos courtesy of American Racing Headers and Dillon Dollar

From the jump we wondered how a free-flowing exhaust might wake up the performance of the highly tuned 5.2-liter engine that powers the latest Shelby GT350. Now that the cars have been on the streets for a while, the aftermarket mods are starting to flow, and one of the newest exhaust products is American Racing Headers’ system, featuring long-tube headers and a high-flow midpipe.

One of the early adopters of this system was SVTP member Dillon Dollar, who brought his Shelby GT350 to True Street Motorsports in McKinney, Texas, to have the car upgraded with the exhaust system and more.

“No one had actual numbers on the ARH system yet and I’ve used them in the past on my 2013 GT500,” Dillon said of his exhaust choice.

Fortunately Dillon didn’t pour on all the mods at once. He walked up the ladder with a baseline, a tune, a JLT Performance cold-air intake, and the American Racing Headers exhaust system (PN ARH-MTSH3-16178300LSNC; $2,089) to illustrate the benefits of each mod.

In the 88-degree Texas air dripping with humidity, Dillon’s GT350 put down 467.04 horsepower and 391.82 lb-ft of torque. With the addition a performance calibration the peak numbers jumped up by 10.49 horsepower and 3.99 lb-ft of torque. Opening up the inlet with the JLT shifted the peak number up by 10.96 horsepower and 8.92 lb-ft of torque. With no tuning changes and the ARH exhaust, his Shelby’s rear-wheel numbers jumped by 18.48 horsepower and 17.68 lb-ft of torque.

“It feels like a whole different animal and sounds like an Indy car,” Dillon added.

We would imagine that jumping from 467 to 506 rear-wheel horsepower would make it feel like a new car, but that doesn’t mean Dillon is done modding his car. Next he plans to switch to E85, swap on a larger throttle body and add nitrous. Sounds like fun.

For more on Dillon’s build, check out his original thread here.


The American Racing Headers exhaust system for the Shelby GT350 features long-tube headers constructed of .065-inch-wall tubing. It is available with either an X- or H-shaped crossover and with or without catalytic converters. In the case of Dillon’s GT350, he opted for the X-pipe sans cats. All versions of the system are designed to join with the factory active mufflers.


True Street Motorsports installed the 1 7/8-inch long-tubes and the companion X-pipe on Dillon’s GT350. The fitment looks great and the results were quite impressive.


Dillon wanted to wake up his Shelby and wake it up he did. By adding an American Racing Headers exhaust system, a JLT cold-air intake and custom tuning, his GT350’s rear-wheel output jumped by 39.93 horsepower and 30.59 lb-ft of torque.


Gray only, please
Established Member
Apr 28, 2005
Awesome results! Thanks for breaking it down step-by-step to show individual gains, Dillon!


Established Member
Sep 14, 2008
The exhaust netted 18hp. Deletion of the cats probably accounted for half of that so the headers alone add about 8-10 hp. Makes me think that the stock headers are not too shabby.

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