In the quest to find the perfect project car, most of us find ourselves browsing ads, searching out a low mileage example. What about a higher mileage Mustang? How would one react to some bolt on performance parts? It’s an interesting question, and one Brenspeed decided to investigate.

Since the introduction of the Coyote engine for the 2011 model year, the price of 4.6 three-valve equipped S197 Mustang GTs has gone down in price. Brenspeed located a 2007 Shelby GT, with 110,000 miles on the clock. The Shelby package added a little power to the car, via a cold air intake, and 91 octane tune. Otherwise this Mustang is pretty much the same as any other 4.6 three-valve of that era in terms of engine and performance potential.

This particular example was well cared for, and that’s key in finding and working with a high-mileage project car. The owners had the car serviced regularly. With that in mind, Brenspeed performed some fluid changes, installed new spark plugs, and fuel filter, and began their testing.

Modifications were done in three stages. Phase one consisted of the maintenance tune up, plus installing a JLT cold air intake, Steeda underdrive pulleys, Steeda charge motion delete plates, and Brenspeed’s own mail order tune via a SCT X4. The results were impressive with the car putting down 305.87 hp and 325.16 ft-lbs of torque once all stage one work was completed.

For Stage 2, Brenspeed decided to add a few of their favorite bolt-on parts to this car. The first being their favorite full length headers and off-road X-pipe from Kooks. The second is a set of Brenspeed’s custom grind Detroit Rocker cams. These cams are designed to increase horsepower and torque, without sacrificing drivability, and also give that loping muscle car idle.

Stage 2 didn’t disappoint, with the car putting down 320 hp with just the exhaust upgrade, and then 343 hp at the rear wheels with the addition of the cams. The real story is in power under the curve, where the cams and exhaust were both generating more total horsepower than what shows up in the peak numbers. This is important because most of the time an engine is working in the lower RPM range.

For the final installment of Project High Mileage, Brenspeed decided to install Ford Racing’s Power Up package, as well as do some drag testing with the car. The Power Up package includes a new Ford Racing intake manifold and a new throttle body. They also installed a new Exedy clutch and flywheel to replace the original stock parts, as well as some BMR lower control arms to get rid of the worn bushings in the stock arms. The car put down a final dyno figure of 357 hp.

The plan was for this car to compete in the True Street class at the NMRA World Finals. With the car on slicks and skinnies, and ready to go, it snapped an axle at the starting line. This brings up another good point about any Mustang, especially a high mileage one. Replacing the stock axles becomes a necessity at some point, the factory units just aren’t going to cut it under high horsepower, especially on a well prepped track, with sticky tires.

Brenspeed did put a new set of Moser axles in the car, and headed to Texas Motorplex for one final bash with the high mileage Mustang project. In Texas, the car managed to pull off a best ET of 12.76 at 109.47 mph. That’s not bad for a car with this many miles, and a few bolt on parts.

This project is an excellent example of how anyone can enjoy having a V8 powered Mustang on a budget, even a high mileage one. There are tons of forgotten three-valve cars on the market, and plenty of enthusiasts who are still holding onto these cars. We look forward to seeing what our fans and Brenspeed’s customers can do with their own high-mileage projects. You can read the full details of Project High Mileage right here at the Brenspeed page, and don’t forget to check out the videos for more details and footage.