Lance Keck, one of Vortech's dyno operators and the guy who'd been dyno'ing the Mach 1 for days, said the car would make another 5 hp if we ran it to death warming the oil, but that was about it. So we pulled the Mach and strapped on the Cobra.
Right out of the gate, the Cobra made 319 hp at 6,400 rpm and 306 lb-ft of torque at 3,850 rpm. The second official run saw nearly identical numbers-319 hp at 6,400 rpm and 309 lb-ft at 3,800 rpm.
We knew the Roots-type blower on the Cobra would make excellent torque down low and would fall behind the Vortech at higher rpm, but we weren't quite ready for such a large difference. The Cobra torque curve simply sky-rockets off idle and lays down gently with advanced rpm, while the Vortech centrifugal supercharger does just the opposite. Comparing torque and power curves, the Cobra and blown Mach just about make an even trade for area under the curve. So, the Cobra is about 50 hp shy of the Mach at the top end, but the Mach trails the Cobra by 90 lb-ft of torque in the 2,400-3,100 rpm range.
The other way of looking at it is the Mach is behind the Cobra up to 4,000 rpm. But, whereas the Cobra makes relatively flat curves all the way across the tach, at 4,000 rpm the Mach's horsepower curve simply soars away from the Cobra. As for torque, the Mach has a nice little bump of extra torque compared to the Cobra between 4,300 and 5,300 rpm-that's how it outpeaks the Cobra in torque.
Vortech was surprised by the strength of our press-car Cobra. The company had tested two private-owner Cobras previously, both of those putting out high-200hp figures on the company's Mustang dyno. Our car was maybe 30 hp stronger than these other Cobras. So a STAR tester was hooked to the Cobra to read out its boost and ignition timing. The Cobra boost started at 7.2 pounds at just 2,200 rpm, an impressively low rpm for such manifold pressure. By 2,600 rpm, it was making 8 pounds. It peaked at 9.5 pounds at 4,300 rpm, then fell to 8.6 pounds at 6,380 rpm, which all sounds correct. The ignition timing was a stout 23 degrees around the power peak, another typical Cobra value. So, it would seem we had a good, fresh, strong-running Cobra.
To The Scales
Our next stop was the truck scales. Modern cars are heavy, as the following chart shows.
| Cobra | Mach 1 |
| Front | 2,080 | 1,900 |
| Rear | 1,580 | 1,560 |
| Total | 3,660 | 3,460 |
| All figures are in pounds. |
Both cars had a half tank of fuel and were weighed without drivers. More importantly, the Mach 1 benefited from its Griggs suspension, which Griggs Racing said should account for a 65-pound reduction on the front axle. Still, at 200 pounds, the Cobra's weight penalty was significant in this test. Even without an aftermarket suspension on the Mach, the Cobra would definitely outweigh the Mach.
Side-By-Side
It's interesting how theory often goes under the bus when the pedal hits the metal. Much of this seems to be less than expert prognostication by those involved-namely us-and some of it is how much perception and emotion count compared to columns of numbers on a dyno sheet.
Going into the side-by-side trials, everyone involved just knew the Cobra would lunge to an immediate-if modest-lead, then be passed by the Mach as the contest continued. We were wrong.