Soon, Siska called AED and told them he didn’t think he could go any faster with the amount of air the M90 could provide. AED’s Scott Graves suggested replacing the Eaton blower with the more efficient, larger-displacement Lyschomb 2300 AX twin-screw supercharger. This supercharger could definetly flow the amount of air Siska needed, so Graves cast a new manifold and the other necessary parts to adapt the Lyschomb to the rest of the original AED kit.
It’s somewhat surprising that the weak rods and pistons in the stock short block stood up to the M90, and Siska knew that with the boost he had in mind, a fully built engine was a must. He started with a new ’03 block bored 0.020-inch over, which increased displacement to 283 ci. A forged ’98 Cobra crank replaced the stock cast piece, while forged Eagle rods and 9.1-compression forged CP pistons did the same for the rest of the rotating assembly. Fox Lake ported a set of ’02 PI heads for the car and installed Ferrea valves and Comp cams beehive Springs. Modmax cams offer 0.525-inch lift and 220 degrees duration on the intake side with 0.515-inch lift and 230 degrees duration on exhaust. The 2.3-liter AED blower pumps 16 psi of boost through these heads and into Kooks mid-length headers connected to ART dual exhaust and Dynomax Race Magnum mufflers. MSD coil packs and a Kenne Bell Boost-A-Spark guarentee complete combustion. A Pro-M 95 mm MAF sensor and 55-pound fule injectors provide the proper air/fuel mix, and the throttle body is a ’95 Mark VIII twin 57mm pice with custom owner-fabricated linkage. Superchips Custom Tuning’s Jerry Wrobleski programmed the car’s engine management using his SCT software. And since Mustang oil pans won’t fit the Thunderbird, a Lincoln Mark VIII pan is the only option for providing additional capacity. Dyno tesing has revealed 560 hp at the rear wheels—that’s supercharged Cobra power coming from a two-valve engine! Though the early 4R70W transmissions are notoriously weak, this one has held up to Siska’s abuse thus far. Improvements, though, include a PI triple-disc 2,800-rpm stall converter and an external Ford fluid cooler.
Cobra owners are well aware of the limitations of their IRS suspensions, and many who are serious about drag racing choose to swap in a solid rear axle. But since every MN12 Thunderbird came with an IRS, swapping in a live axle is a huge undertaking, and Siska thought it made more sense to tune it as best he could rather than to back-half the car. The rear springs are stock but feature helper airbags, and urethane bushings in the knuckles prevent wheel hop. Bilstein built the rear shocks, which are actually ‘03-’04 Cobra components, but they fit in the car and work well.
Siska removed the stock IRS centersection and replaced it with an aluminum housing from a Mark VIII and then installed 4,10 gears, a Detroit Locker differential and urethane bushings. A differential cover brace from MN12Performance.com guards against breakage where the centersection mounts to the body. Likewise, an MN12Performance.com pinion brace keeps the snout from moving under load. These upgrades keep the centersection put, so it can transfer power efficiently through the Raxels half-shafts to Mustang Cobra wheel hubs. Swapping over to the Mustan hubs allowed Siska a greater choice of wheels (MN12-platform cars feature an oddball 5x4.25 wheel bolt pattern), and with this greater flexibility he chose 15x8-inch Weld Pro-Stars. His tire of choice is the 295/60-15 Mickey Thompson drag radial. The ’95 Thunderbird is not a light car, so the owner opted to install an AJE Racing tubular K-member and control arms to remove nose weight. KYB shocks and stock springs aid in transferring the weight that’s left to the rear wheels off the line. He also replaced the stock 10.8-inch fron discs with 11.5-inch Mark VIII rotors redrilled to fit SN95 Mustang hubs. Skinny 15x4-inc Welds are another concession to weight savings, and they spin 15x17.0-inch Moroso Drag Special tires.
With the exception of the cowl hood, the entire body is stock. Despite their bulkk, these are good-looking cars, and the owner saw no reason to alter the factory design. The American Sports Car cowl hood was a necessity demanded by the AED blower, and even then Siska had to modify the underside of the hood for extra clearance. He had his dealership paint shop spray the hood in matching Sikkens paint. And since so many cars running slower than this one wear a cowl hood for looks alone, the car can still pull off the sleeper look at the track or on the street.
The interior provides a bit more of a clue as to th Bird’s true nature. If you’re lined up next to Siska in the staging lane, you’ll do well to notice the substantial rollcage—it’s not there for looks, but rather because the NHRA says it has to be. The cage provides attachement points for the RCI five-point harnesses that strap driver and passenger into the stock gray leather seats. The rear seat is gone, but that’s the interior’s only concession to shaving weight. The rest of the interior is still there, and as it should be, this Thunderbird is still a luxurious ride. The A/C and factory CD player are still there, too. So, the big question is, with 3,950pounds of Thunderbird, what wil 560 RWHP and plenty of traction get you? The answer is a startling quarter-mile time of 10.57 seconds at 129.7 mph, a time that has left plenty of Cobra, Corvette, and Viper owners wondering how the family car left htem so far behind. Siska isn’t quite done tuning, either. He says he’s still cooking up a plan for the coming year, trying to figure out his next set of goals. He's confident that sooner or later he’ll have the Thunderbirdin the 9s, and based on his attitude, determination and past performance, we have no cause to doubt him. Siska has driven this car as far as the Carlisle Ford Nats, and he took it to the first four Modular Shootouts from 1999 to 2002. You can bet he’ll have it back on our track next year, too, so if you’re in the other lane, you’d better hope for a holeshot.
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