Since Ford shared how much power the 2020 Shelby GT500 will make, in addition to how much it will cost you, owners of the previous generation GT500 might feel it’s a good time to make some upgrades.

But what if your car has more than 100,000 miles on it? Should you really mess with its high-mileage Modular or Trinity?

Brenspeed, the Mod motor Mustang experts located in Indiana, got their hands on a one-owner 2009 Ford Shelby Mustang GT500 with 106,000 miles on it. According to the video, the car received a 2.9-liter Whipple twin-screw supercharger, in addition to a few other performance parts, and made 658 hp to the wheels on 93 octane.

According to Brenspeed, the Whipple W175HPR, known as the supercharger of choice for the Ford Racing Cobra Jet programs, produces incredibly high power levels with the stock 5.4-liter Shelby GT500 engine as well as highly modified engines.

The Whipple serves as a direct bolt-on replacement and gives the owner the ability to run higher boost levels than the factory 2.1-liter 122ci roots-type supercharger. The W175HPR Gen 3 compressors can run nearly 25 psi of boost, though at that level some engine modifications may be required for performance.

The W175HPR supercharger has an optional mono-blade throttle body for nearly 1,900cfm capability and a 127mm inlet tube with 120mm round MAF housing which allows significantly more flow.

Additionally, Brenspeed says that a simple pulley change will allow the owner to step up or down for driving on the street or track, which will enable them to really dial in their Shelby.

Other highlights of the Brenspeed-provided Whipple supercharger is that it fits under the stock hood and it is 50-state emissions legal up to 16 psi, though it has been optimized for boost levels over 15 psi with its increased built-in-pressure ratio.

The complete bolt-on system comes with all the necessary parts for 17-pounds of boost, including a PCM reflash for reliability and power.

Kit Includes:

  • 2.9L Compressor
  • 3.25-inch Supercharger Pulley (17 psi)
  • Fuel Pump Voltage Booster
  • Dual 68mm Throttle Body
  • 123mm Cold Air Intake
  • Spark Plugs
  • Calibration

Other modifications added to the build include a set of JLT Direct Fit Oil Separators, Kooks Headers, and DeatschWerks 95lb Injectors.

According to Brenspeed, while the engine is venting crankcase pressure through the intake track, the oil becomes a vapor and large amounts will coat the intake manifold, blower rotors, intercooler fins, and can even dilute the gas which effectively lowers the octane level. All engines experience this phenomenon but made worse when they are supercharged because of the crankcase pressure increase.

The JLT Direct Fit Oil Separator has OEM lines already attached, so it is a direct plug and play.

The JLT Oil Separator has been milled from solid billet aluminum and features a knurled tank base for easy removal to drain the excess oil, and an O-ring seal to prevent any leaks.

Brenspeed says that JLT took the unit a step further and added a Ford Motorcraft metal mesh PCV pre-filter element to collect the last bit of oil droplets and drains back into the tank when the engine is shut down. The tank holds 2-ounces of fluid, Brenspeed recommends that it be removed with every oil change so that it never gets close to being full.

Brenspeed also added a set of Kooks headers which are made of 304-grade stainless steel. Kooks says the headers are welded with stainless wire, the oxygen bungs are stainless, and they come with a lifetime warranty. No coating is necessary and all of the installation hardware, such as O2 extensions, and gaskets, are included.

Lastly, Brenspeed added a set of DeatschWerks 95lb Injectors to this 2009 Mustang. The injectors are compatible with E85 and feature flow rates and set balancing in-house by DeatschWerks. The fuel pressure range for these injectors is 40-80 psi, while the minimum pulse width set to 1.0 ms and the maximum duty cycle is 93-percent with 12.4-ohm coil impedance.

Final dyno numbers revealed the Brenspeed upgrades added 100 horsepower which amounted to a total of 658 horsepower and 621 lb.-ft of torque.