Michael Galimi
August 5, 2010

The positive side of the 750hp kit is that it is 50-state emissions compliant, which is amazing given its extreme output. The 50-state legality is only when the FRPP tune is utilized. Kershaw continues: "There are many cases of customers getting one of our kits and then immediately having the calibration re-done to find more power. Those calibrations, however, do not have the durability built in like the FRPP tune. It's common to see catalyst failure and exhaust valves take a tulip shape from the exhaust heat in those cases. In addition, custom tunes do not have emissions approval."

This kit was designed specifically for the '10 GT500. It can't be used for '07-'09 Shelby GT500s due to the calibration difference, as well as the inlet system. Ford Racing sells a specific '07-'09 Shelby GT500 supercharger upgrade system. Its boasts 605 hp (at the crank), and the factory warranty remains if it's installed by an authorized Ford Racing shop.

Kershaw noted that Whipple offers a tuner kit directly; it fits '07-'09 models as well. The system produces the same 675 rwhp that we witnessed from the FRPP kit we tested on the '10 GT500 model.

Shaun Lacko and Bob Cook of Downs Ford Motorsport handled the installation; we then made the short drive to Big Daddy Performance for chassis dyno testing. The installation was easy and straightforward, except for the rear bolt on the supercharger. Lacko had to make a custom tool to reach it. The custom tool was basically a straight metal bar with a wrench welded to the end of it. The makeshift tool allowed Lacko to reach the bolt and tighten it down. Other than that, it was a simple blower swap, drop-in fuel pump assembly, and ECU recalibration.

On the dyno, the 2.9L supercharger peaked at 19 psi at the top of the pull, and the dyno read 675 rwhp and 629 tq. That was up from our baseline of 501 rwhp and 474 tq-gains of 174 rwhp and 155 tq.

"There is a bit more left in the tune," said Dwayne Gutridge of Big Daddy Performance as he pointed at the air/fuel mixture. The FRPP tune showed a consistent 12.5:1 A/F ratio, and "the 4.6L and 5.4L modular engines, whether it be the Two-Valve, Four-Valve, or Three-Valve-any of them-like to run rich in the 11-11.5:1 range," says Gutridge.

Adding more fuel to our test GT500 would have netted more power-Gutridge wouldn't say how much, but we wouldn't be surprised to see 700 rwhp. Although, as Kershaw stated earlier, doing so would eliminate the emissions-legal status of the kit.

The 750hp package instantly puts the '10 Shelby GT500 into ZR1-slaying territory-just add sticky tires.

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