As we mentioned before, MM&FF showed a brief glimpse of the available power when we installed a smaller blower pulley onto a preproduction coupe. An easy 40 hp at the wheels turned the snake into a tire-burning monster. And where centrifugal blowers ruled in the Mustang market, owners now saw the potential of a Roots-style compressor. Today, blowers from KB, Roush, Saleen, and Whipple are as popular as units from Paxton, ProCharger, and Vortech. And one could argue that it's due to the Terminator. Meanwhile, enthusiasts found that an air intake, a tune, and exhaust mods were worth another 40-80 hp. These days, 500 rwhp is just $2,000-$3,000 away, and extremely common among Cobra owners-try that with a Corvette.
We asked some of the hottest tuners what the limits are for the Terminators, and the results were quite impressive. Joe Panciarello of Mustang Magic in Deer Park, New York, told us that his own personal ride "makes over 600 to the tires and still gets 20 mph on the highway, and passes (New York State) inspection." Most of the other tuners estimates are around the same level.
"I've seen Cobras making over 800 driving on the street, but the bottom line is what you feel is 'streetable'," says Jim D'Amore Jr. of JDM Engineering in Freehold, New Jersey. "I have a lot of guys who won't put anything less than 103 octane in their Terminators, and they consider it their daily driver. A daily driver running on minimum 91 octane and getting a good, strong life from the stock engine will deliver 600-650 hp at the tires.The cool thing about today's technology and tuning is that we can make 600, 700, 800, or more horsepower and still turn the power down to a conservative amount for the street, with just a simple tune and lowering of the boost level."
Johnny Wiker, of Johnny Lightning Performance, says, "JLP has built three high-to-low-10-second Cobras running as fast as 137 mph in the 1,320. All are street drivers with IRS, six-speeds, and ice-cold air conditioning."
That's a stout package for any street car, but the fact is, not many hot rods can deliver the goods like the supercharged SVT Cobra. "[Terminators] are definitely one of the best buys on the market for your 'bang for the buck' performance," says SLP Performance Part's Brian Reese. "They're very capable of 700 hp to the tires on a factory engine. That's hands-down unbeatable."
With that kind of power and torque readily available, the Cobra's independent rear suspen-sion, a feature unique to '99-and-later SVT Cobras, has been criticized for not holding up when the power is put down. Wheelhop in the first iteration of the Cobra IRS was rather noticeable, so in 2001 Ford added better bushings to solve the problem. Obviously, the whopping increase in power for the 2003 models required further development of the IRS, and this resulted in even stiffer bushings, as well as thicker axle shafts.
IRS failures usually occur at the dragstrip where traction is plentiful. Having witnessed numerous abbreviations in IRS life expectancies at events all over the country, we can tell you there are two main causes. The first problem comes from inexperienced pilots who believe they can drive through wheelhop. Keeping the pedal down once the car has started bouncing will, nine times out of ten, end in breakage and a call to AAA.
The other main cause for failure is a combination of shock load from a clutch drop and/or the differential housing moving around in its carrier. When the diff moves, it dissipates torque throughout the aluminum case-rather than the ring-and-pinion gears, which are designed to handle that sort of pressure-and it can blow apart. This won't be an issue with the Shelby.
Terminator owners who frequent the dragstrip have been known to swap out the IRS for a solid axle. It's a fairly easy job. We've seen quite a few solid-axle Cobras and thought the swap was pretty common, but as we found out, that's not the case. After surveying some shops and a generous amount of Cobra owners, we learned that most enjoy the IRS and plan to keep it.
"While my old solid axles were more forgiving with hard launches, the IRS keeps all four of my tires in contact with the pavement during tight maneuvers, and has made me see the IRS light," says Mystichrome convertible owner R. David Jones. "It has a much smoother ride with the IRS when I'm just cruising around town, too."
"Comparing my '97 Cobra versus the '03 Cobra driven on the same rough roads, the '97's (solid) rearend would be all over the place, and the '03 with the IRS would remain planted," says Rexford Dundon.
The Mustang chased the F-body ponycars until 2003, when the supercharged engine was backed by the T56 six-speed transmission. | 
Prior to the '99 new-edge Mustangs, the SVT Cobra used a solid, straight axle to put the power to the ground. | 
IHRA Pro Stock racer Robert Patrick is just one racer who carries the SVT banner into drag action. Though not a real Shelby, his '06 tube-chassis, Jerry Haas-built Mustang looks the part and runs mid-6s in the quarter-mile. |