Everyone was bone tired when, at around 11:30 p.m., the key was cranked and the newly muscled GT came to life and idled perfectly with its Pro-M Racing chip in place-not always the case, as we all know, after installation of a power adder. Unfortunately, we had to boogie and couldn't stick around to watch the next day's dyno session or drive the beast. So we'll have to let the above dyno results do the talking. We've also included Mustang dyno results for a stock '03 Cobra for an interesting comparison-333.4 peak horsepower at 5,700 rpm.
As you can see, peak horsepower was up by more than 60 percent to 373, while torque got a 52 percent boost to more than 415 lb-ft-and, remember, these numbers were generated on the always-conservative Mustang dyno. More important from a daily driving aspect than the peak numbers are some point-to-point observations. By 3,000 rpm, torque is already improved by more than 96 lb-ft, and at 5,000 rpm, power is elevated by more than 141 ponies and torque by more than 148 lb-ft. Speaking of torque-something a stock 4.6 lacks in spades and that a 3,850-pound convertible can really make use of-it crests the 300 lb-ft mark by 2,500 rpm and tops 400 lb-ft by 4,000 revs. This is with a mere 6 psi of boost and what Pro-M Racing's Scott Beer describes as a "very conservative and safe" tune.
As indicated, I didn't get a chance to drive the muscled-up ragtop, but car owner Joe Clark-the most important critic of all-says it "runs and drives great." His biggest problem seems to be how to find traction for all this newfound power at the strip.
Note: The baseline run includes a Pro-M 80mm mass air and cold-air kit, a ported upper intake, and a 70mm throttle body.