We all know the importance of getting power to the ground. To date, applying all of our project car's horsepower to the street or racing surface has been a challenge, as drag radial and DOT-approved street tires have worked OK (the best 60-foot with Mickey Thompson ET Streets was 1.594), but we're certain we'll have better results all around if we use a traditional slick tire on the rear of our coupe. That said, we're making the upgrade to Mickey Thompson's ET Drag slicks in the 28x10.5x15-inch sizing that has been synonymous with Fox-body Mustang drag racing for a long time.
We also decided to roll the 'Stang onto the hoist at B&D Racing for a check and reset of rear suspension and pinion angle. Horsepower has its best chance of getting to the rear wheels when the driveline is as straight as possible, so Mase Rowland is checking all of our rear suspension's angles and making the necessary adjustments to ensure we'll have good launches and clean runs.
The results of our latest dyno testing and our desire to nail down a perfect run prompted us to make another tire change for this track test. We're replacing the Mickey Thompson 27x10.50x15-inch ET Street (DOT approved) rear tires with full-on ET Drag slicks (off-road use only). Because our project car is heavy, we've selected the "S" (stiff sidewall) version of MT's popular 28x10.5x15-inch racing rears.
Saul "The Surgeon" Gutierrez of Extreme Automotive removes both of Chris Alston's Chassisworks lowers, shortens their lengths accordingly, and then reinstalls the arms. The change creates the necessary clearance for mounting the rear wheels and slicks without a problem.
Similar to an NMRA EFI Renegade 'Stang, the "true 10.5" tire tucks neatly underneath the back of our T-top coupe. No, we didn't sneak minitubs back there, but the wheelhousing modifications we made to fit Mavromont Industries' Pony R 17x10-inch rear wheels and big 315 Nitto street tires on our project coupe ("Real-Deal Wheels," June '08, p. 72) help achieve this look and stance with the slicks, which are mounted on Weld Alumastars (15x8.25-inch with a 5-inch offset and 5-inch backspace). We saw a 0.034 improvement in the coupe's 60-foot e.t. with a change to slicks.
Our first attempt at mounting the new slicks exposed this minor problem. Despite the rear wheelwell being rolled, the back of the tire makes contact with the lower portion of the housing, which tells us that the coupe's lower control arms must be adjusted.
Brian Schapiro and Mason "Mase" Rowland of B&D Racing made time for us to bring the coupe into the shop to verify and adjust pinion angle, as it hasn't been properly set since the car has been up and running. A drive-on hoist is required for this task, as the 'Stang should be resting on its full weight with the tires adjusted to the correct air pressure before making any changes.
Mase removes the driveshaft and marks each Chassisworks double-adjustable upper control arm.