Last month, you may have caught us testing a proposed theory on our resident '93 Cobra project car, Stolen Goods. The test, in fact, was nothing more than your average intake manifold swap. The theory was that a different manifold, namely the Edelbrock Performer RPM II, would pick up 20 or so horsepower, but lose 30 lb-ft in the process when bolted to our D.S.S. Racing 347ci engine. To our surprise, we picked up power and torque across the powerband.
Originally, we had picked out a torque-enhanced combination of induction parts for our Ford Racing Performance Parts (FRPP) Boss block-based 347 bullet, and it provided us with just that at 358 rwhp and 376 lb-ft of torque. The Edelbrock intake manifold produced 372 rwhp and 383 lb-ft of torque, with this sizeable gain seen across the entire rpm range. Peak power was still at a valvespring-friendly 5,800 rpm and change, and driveability seemed to increase with the new intake manifold.
Last month, we installed the intake and dyno-tested the Cobra. This month, we wanted to install a steeper gearset to see if we could reduce our elapsed time and put this snake into the 11s. First, however, we took it to the track to baseline it with the 3.55:1 ring-and-pinion ratio putting the power to the ground.
We Picked Up 14 rwhp and 7...
We Picked Up 14 rwhp and 7 lb-ft of torque when we switched to this Edelbrock Performer RPM II intake manifold. We also improved our quarter-mile elapsed time and speed.
Ford Racing Performance Parts...
Ford Racing Performance Parts provided us with a 4.30 gearset (left, PN M-4209-G430M) and a 3.55 gearset (right, PN M-4209-G355A), as we were returning Stolen Goods to the 3.55:1 ratio after this test to maintain the long legs it will need on the road course.
We Also needed toexchange...
We Also needed toexchange the Torsen differential for something that could handle dragstrip abuse. We hadn't broken the Torsen with the many clutch drops that we had already performed, but we didn't want to take the chance of it happening at the track, so we ordered this Traction-Lok unit from FRPP. This particular unit, PN M-4204-F318C, is the same differential from the '03-'04 Cobras. It features carbon-fiber friction plates and is set up for 31-spline axles. We also used FRPP's installation kit (PN M-4210-A).
Project Stolen Goods was driven an hour and a half to Bradenton Motorsports Park in Bradenton, Florida, where we mounted our Mickey Thompson 275/40/17 drag radials. With the Flex-a-lite electric fan/radiator combo and our Meziere electric water pump circulating the coolant between rounds, we were able to make all of the passes at a relatively cool 160 degrees of coolant temperature.
Launching at 3,500 to get the feel for the track surface, the Cobra bogged slightly and took off with a 1.82 short time. The quarter-mile flashed by in 12.22 seconds at 114.02 mph. After our first pass out, we already eclipsed our previous best of 12.58 at 110 mph.
Seeing as how the track had considerable bite, we raised the launch rpm to 4,000. The transfer of energy loaded the clutch hard at the launch, and Stolen Goods leapt to a 1.80 60-foot time. We crossed the stripe in 12.12 seconds at 114.50 mph. The following run after that netted a 12.20 at 114.35 mph with a 1.81-second short time. We were pleased with the results thus far, but there was still time for one more go at the 1,320. We decided to raise the launch rpm further to 4,500 rpm, but by then, the track had gone away, and wheelspin abounded in First and Second gear. A 1.88 60-foot time followed by a 12.51 at 113 mph was the result. Still, we dropped over 0.4 second with the new intake manifold.
We were close to the 11-second zone, but hadn't hit it yet, so we put in a call to FRPP and ordered up a 4.30 ring-and-pinion gearset, along with a 31-spline Traction-Lok rear end. Steeper gears are usually a sure way to quicker elapsed times, and we thought the 4.30s should get the job done.
To install the 4.30 gearset,...
To install the 4.30 gearset, Hermann Stolzenburg of Horsepower by Hermann dropped our Panhard bar, then took off the differential cover to expose the centersection of the rear axle so he could remove it.
A Hydraulic press was used...
A Hydraulic press was used to install the carrier bearing onto the new Traction-Lok differential.
The Pinion gear received the...
The Pinion gear received the pinion bearing using the same press.
Until now, we'd been using the Torsen T-2R differential, but Torsen does not recommend performing clutch drops with this differential. We decided to pull it out before we caused serious damage to the rather costly unit, and swapped it out for the Traction-Lok. FRPP also provided us with an installation kit and a bottle of friction modifier to add to the differential fluid.
For the installation, we drove about five minutes down the road from our MM&FF Southern Command Center to Horsepower By Hermann (HBH), located in Tampa, Florida. Owner Hermann Stolzenburg has been in the Mustang business since the beginning and was even a contributor a time or two to MM&FF in its early days. The majority of HBH's business comes from word of mouth, so you know he has a good reputation for doing things properly. Plus, he's just a great guy to work with. Stolzenburg is in the process of relocating HBH back to Maryland, but we were able to get Stolen Goods booked in right before the move.