Shelby GT 500 Bolt-Ons - Top To Bottom

How's this for climbing right up the horsepower ladder? The AFM crew took Jeff Reasons' '07 GT 500 from 415.25 hp at the tires all the way up to 544.93 to the ground. That's impressive stuff. As you can see, a huge gain (53.89 hp peak to peak) came from replacing the restrictive factory airbox with the PMAS Velocity meter and Power Pipe. Just the Predator Performance tune tacked on another 27.11 peak horsepower, and the Metco pulley made good with 23.57 peak horsepower. Meanwhile, the Bassani mufflers clocked in with 6.31 peak horsepower, and the rest of the exhaust added 18.8 for a total of 25.11 peak horsepower. We know the stock systems on the latest Mustang are good, so when Rick described this as the most power he's seen out of an exhaust system, that's high praise indeed.

Of course, it's sexy to talk about the peak numbers, but it's the area under the curve that you really feel. As you can see in the column showing the difference between the baseline and this package of parts, that the gains are impressive for the duration of the pull, that's power you can feel. Bolt-ons have really come a long way.