Stronger Venom

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  • The core of the GT 500 package is Paul’s Stage III package, which includes a ported and polished supercharger case, inlet elbow and throttle body. Also included are new pulleys, a cold air kit and custom tune. - 1
  • We got the project started with shifter mods, which included replacing the soft stock bushings with solid bushings of Paul’s design. - 2
  • This photos shows the aluminum shifter bushings that replace the rubber stock parts, greatly improved the feeling of accuracy and immediacy of the shifts. - 3
  • The underbody shifter linkages also get new bushings from Paul’s. It’s not an easy swap, but delivers a noticeable improvement in shift quality when completed. It’s a whole lot easier to do, too, with the driveshaft removed and the car on a lift. - 4
  • With the car still up in the air, the rear springs were swapped with those that lower the car’s rear by about an inch and a half. - 5
  • Choices for replacement wheels on the GT 500 are few and here’s the primary reason: The ends of the sway bar stick out precariously, interfering with many aftermarket wheels. - 6
  • Here’s how the GT 500 looks with its new set of rear springs. The stance is evened out, giving the car a more balanced, hunkered-down appearance. - 7
  • Next up is the engine mods, but they’ve begun much earlier in another part of the shop, where the supercharger case, inlet elbow and throttle body were ported, polished and port-matched. - 8
  • Paul’s modified intake elbow (right) is show with a stock elbow, demonstrating the difference in appearance. The factory parts’ air passages have the same, rough casting feel as the outer cases. Paul’s work smoothes the air passages, enhancing airflow. - 9
  • Under the hood of our project car, the blower swap begins with the disassembly of ancillary components, such as the fuel rails, as well as the factory air intake system. - 10
  • Next, the throttle body and intake elbow are removed. - 11
  • The supercharger is surprisingly easy to remove, as it lifts straight up from the manifold. Of course, we didn’t have room to show every nut and bolt that was unbolted to reach this stage, but for the most part, it’s a relatively easy removal process. - 12
  • No sooner does the old blower come off than the ported version is installed. Paul’s will also port and polish a car’s original blower for those who don’t want to go the exchange route. - 13
  • With the ported blower in place, the stock pulley is carefully pulled off the snout with a tool designed by Paul’s High Performance. This is a job for professionals because, well, you’re screwed if something breaks. There’s no service replacement – you’ll be ordering a new blower. - 14
  • Next, the new pulley, which helps pump up the blower’s boost, is attached. A new idler pulley is included, too. - 15
  • With the blower installed, the top of the engine is reassembled, including the port-matched inlet elbow and throttle body. - 16
  • The engine was finished off with one of Paul’s cold-air intake systems. - 17
  • Apart from the cold-air kit, there’s nothing to hint at the enhanced capability of this supercharged engine. - 18
  • A Maganaflow cat-back exhaust system enhances power and helps reduce exhaust temperature of the pumped-up Shelby. - 19
  • In stock trim, our black project car made 412 rwhp and 399 lb.-ft. with the ported blower and other mods, rear-wheel power jumped to an astonishing 556 horses and 524 lb.-ft. - 20
  • Dyno graph charting before-and-after performance of our GT 500 project car. - 21
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by Barry Kluczyk  More from Author

How To Use Tried And True Tricks To Extract A Vicious Bite From A Shelby GT 500

With 500 horsepower from its supercharged V-8 engine, you’ll find few who would argue the Shelby GT 500 is a slouch. Still, what the factory delivers is merely the starting point for many enthusiasts and if, say, FoMoCo delivered a 950-horse Mustang, there would a full-court press underway in the aftermarket to reach the 1,000-horsepower level.

It’s for those who can’t leave well enough alone that businesses such as Paul’s High Performance thrive. And no sooner did the GT 500 hit the ground than customers’ cars hit Paul Svinicki’s chassis dyno. Svinicki has developed a homegrown performance package for the GT 500 that pumps up rear-wheel output from the stock 415-hp level to more than 550 horsepower.

The power increase comes via the following:

• Ported and port-matched supercharger case, inlet elbow and throttle body

• Cold-air induction system

• Cat-back exhaust system

• Custom calibration


Our black GT 500 project vehicle produced 412 rear-wheel horsepower in stock trim, along with 399 lb.-ft. of torque. After the go-faster parts were added, rear-wheel output jumped to 556 hp and 524 tugboat-like lb.-ft.

The engine mods comprise Paul’s “Stage III” GT 500 setup and the one on our project car included a pulley change. Additionally, the GT 500 package includes new shifter bushings that firm up the shift action and rear lowering springs, which give the car a more balanced stance. All the parts, labor and dyno tuning add up to roughly $5,000 worth of work at Paul’s Jackson, Mich., shop. That’s less than the cost and installation of a supercharger for a naturally aspirated engine yet it delivers about the same power boost – along with an improved shifter feel, exhaust and lowering springs. In our book, that’s a value.

For a little extra out of your checkbook (well, “a little” is a relative term – ask your wife, first), a Whipple supercharger will replace the factory Eaton unit and output increases exponentially. We recently followed along with the installation of the Stage III parts, the exhaust, rear springs and shifter and were impressed with the quality of Paul’s custom components and relative ease at which they were installed.

In a reversal of the “Terminator” cars, where supercharger removal/replacement is a bear and a shifter swap is a snap, the GT 500 cars feature killer shifter swaps while the blower swap is a relative cinch. The compressor simply lifts straight off the manifold.

In addition to the increased performance, Paul Svinicki reports another bonus of the package: Lower exhaust temperature.

“The exhaust temps drop by up to 30 degrees over stock,” he says. “It’s a dramatic difference.”

Paul’s also sells the individual components of the GT 500 package separately and maintains a stock of ported/polished blowers that can be had on an exchange basis (with the requisite core charge). If you’re within driving range of Jackson, Mich., however, it’s worth a couple of days to take your car to the shop for a personal installation and tune. This should be particularly considered if you want the blower pulley changed – it’s not an operation for the weak of heart or inexperienced wrench turner.

We’re constantly amazed at the relative ease at which so much more horsepower seems to flow readily out of an uncorked GT 500 engine. And Paul’s High Performance proves that it doesn’t take an unlimited credit balance or Unobtanium parts to produce unbelievable results.



Paul’s High Performance

Jackson, Mich.

(517) 764-7661


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