Marc Christ
Brand Manager, Modified Mustangs & Fords
March 31, 2014
Photos By: Kristian Grimsland

Though we chose no supercharger, turbocharger, or nitrous, the 427ci Kaase powerplant that is destined for Hypersilver made an impressive 601 horsepower and 614 lb-ft of torque—on 93-octane pump gas. Below 4,000 rpm, it still produces over 600 lb-ft of torque. So even if we were going to feather-pedal this thing around town (which we're not), it still needs drivetrain components up to the task of handling that much torque on a regular basis.

Last month, we installed the Wilwood brakes and Moser 9-inch internals. There's no question about the rearend being strong enough. But in between the engine and pinion flange remains a large void for a host of moving parts like the clutch, transmission, and driveshaft. All of these must independently be strong and durable enough to handle the 600-ish lb-ft that our Windsor demands.

Furthermore, since this is our ultimate Fox-body, they must also handle and transfer the power to the rear wheels in a smooth, quiet, and reliable manner. Sure, there are a slew of "race" transmissions and clutches on the market that could handle this level of power with ease. But an on/off clutch, heavy pedal, straight-cut gears, and no overdrive weren't on our list—not by a long shot.

And when it comes to putting down big power while maintaining street manners, the obvious choice is a Tremec transmission. Tremec has been a leader in the OEM and aftermarket manual transmission markets since 1964. The engineering and technology that it develops and manufactures through its OEM division trickles down to its aftermarket division. The result is a full line of five- and six-speed transmissions that provide high-torque capacities; reliability; quiet operation; and smooth, crisp shifts.

Our choice was the Magnum (formerly known as the T-56 Magnum), which is actually more related to the GT500's TR-6060. This "sledgehammer in velvet gloves" is a six-speed capable of handling 700 lb-ft of torque. And since we're weighing in at almost 100 lb-ft less, we're leaving some room for improvement down the road. Sure, the venerable TKO-600 would have sufficed, but we wanted breathing room—and the double overdrive, of course. And at $2,895—$500 more than the TKO—we couldn't resist.

There are a number of companies that are now offering complete drivetrain kits to install one of these beasts into your '79-'04 Mustang, but we decided to piece it together ourselves. We already had Ryan Lowther at Demon Motorsports cut out the stock crossmember and fabricate a new one, which he connected to the subframe connectors (before we went to paint). So all we needed was a clutch, bellhousing, and driveshaft.

The clutch market is flooded with twin this and dual that, but we recently learned about Centerforce's latest design, the DYAD DS. This twin-disc clutch is designed to offer a torque-holding capability of up to 1,300 lb-ft, while providing smooth engagement, quiet operation, and a light pedal feel—everything we want and need. It comes fully assembled, so installation is stress-free and straightforward.

Centerforce's DYAD consists of a lightweight flywheel, drive disc, quiet floater, floating disc, and ball-bearing pressure plate. It features all ARP hardware, and comes with index marks to ease installation.

Each also comes with its own information form, which includes the date of manufacture, serial number, measurements, and holding capacity. Each clutch is tested before it leaves Centerforce's facility, and ours passed the test with an average holding capacity of 1,371 lb-ft—more than twice our demand. (Check out the DYAD video HERE!).

To house our clutch, we turned to QuickTime for its 5.0L/5.8L bellhousing for T-56 transmissions (PN RM-8031; $558.95). This SFI-approved piece does tip the scales at 20 pounds, but provides priceless protection against a clutch failure should one occur. All necessary hardware is included.

Once the clutch, bellhousing, and transmission were installed, we measured for our driveshaft.


Shaft Tech

With over 600 horsepower, Hypersilver will certainly need more than a stock-style driveshaft. So we turned to Axle Exchange for a custom 4-inch piece.

"Our shafts are built to high standards using the very best parts," says Anthony Pozzuoli of Axle Exchange. "The 6061 tubing comes directly from Alcoa, and our wall thickness is thicker than other aftermarket driveshafts, allowing for higher horsepower ratings. Our shafts are machine-welded, high-speed balanced, and built with heavy-duty Spicer joints."

Photo Gallery

View Photo Gallery

So we measured for length, gave our specs on transmission and rearend, and in a couple of days, a shiny aluminum driveshaft showed up on our doorstep. But Axle Exchange doesn't just make custom driveshafts.

"We offer a large selection of driveline components, as well as complete assemblies," says Pozzuoli. Of course, it offers pre-made driveshafts to fit most Mustang applications from '79-up, as well as brake kits, clutches, and steering racks. For more information, go to www.axle-exchange.com.


1. Assembling the rest of the drivetrain components, we turned to Centerforce for its new DYAD DS twin-disc clutch (PN 04115700; $1,576.39).
2. This quiet-operating twin-disc features a flywheel, drive disc, floater, floating disc, and pressure plate. The flywheel and drive disc are shown here.
3. ARP fasteners are used to assemble the clutch, and the round alignment pins seen here align the floater and keep it from rattling.
4. Here is the floater sitting in place against the drive disc. The drive disc is splined, and is the part that drives the input shaft on the transmission.
5. The floating disc is next, and locks into the six pins located on the hub of the drive disc. The floater and floating disc work together to dampen the shock of clutch application and also allow for a lighter pedal while maintaining a superior torque holding capability.
6. We chose Tremec’s Magnum transmission for this project. Formerly known as the T-56 Magnum, this six-speed actually shares most of its components with the venerable TR-6060, found in the GT500.
7. This bad boy features six forward gears (2.66, 1.78, 1.30, 1.00, 0.80, 0.63), two of which are overdrives.
8. It has a 26-spline input shaft and 31-spline output shaft, and is capable of handling 700 lb-ft of torque.