In the early spring of 2003, Gary Winter went to his local dealership to buy a pickup truck. On his way to the sales office to complete the truck transaction, he was so taken by the lines of a brand new 4.6L-powered Mustang Mach I that he forgot all about the truck.

Eleven years later, Winter and his Mach I are on the cusp of running nine second quarter miles.

With the exception of the Billet Specialties wheels, the outward appearance of the car has not changed. However, Gary swapped out the 4.6L 4-valve engine for a Ford Racing 5.0L Boss block and stronger internals. Built by MV Performance of Winder, GA, the engine measures 324 cubic inches, uses the factory cylinder heads, and sports a new intake manifold and a BigStuff3 EFI controller. It makes 505 horsepower at the flywheel and can rev to 9,000 rpm. The original five-speed transmission has also been replaced as Winter elected to upgrade to a Tremec TKO 500 with a Quick Time bellhousing. Out back, the 8.8 inch rear end has been upgraded with Moser axles, a Strange spool, and 4.88 ratio gears.

“I was cutting the lights at 7,800 rpm, so we altered the rear gear ratio from 4.56 to 4.88:1,” Winter said. “With the lower gear, we’re aiming to exit the quarter mile at 8,300 or 8,400 rpm. It also eases the loading on the clutch system.”

To handle the car’s 505 horsepower, Winter decided to have a new RAM Powergrip clutch assembly and billet aluminum flywheel installed. The single-disc clutch provides 30 percent greater holding power than a stock clutch and can handle up to 550 horsepower with no appreciable increase in pedal feel. The SFI-approved billet aluminum flywheel is 14 pounds lighter than the factory flywheel. The flywheel’s reduced rotating weight allows the engine to rev quicker, but it still retains enough mass to resist heat distortion that could adversely affect clutch performance. Like most modern performance cars, the Mach I has a traction control system.

MV Performance took us through the installation of the RAM clutch and flywheel assembly. It’s a smart upgrade for any serious street performance or race car.

2003 ford mustang mach 1
removing the shifter and boot from a mustang
oxygen sensor installed on a set of headers
slowly lowering an exhaust system prior to full removal
marking driveshaft prior to removal to ensure proper balance
removing transmission from an sn95 mustang
clutch and flywheel exposed after bellhousing removed
a new billet aluminum flywheel compared to a old worn flywheel
a side by side comparison of a new and worn clutch disc
installing a flywheel and clutch assembly
removing bolts from a clutch
view of a throwout bearing on a mustang clutch
quicktime bellhousing installed in an sn95 mustang
jacking up a transmission for install into a mustang
moving clutch fork to examine clutch play
removing electrical connectors prior to removing driveshaft

Gary Winter’s 2003 Mustang Mach I is a street/strip warrior that’s knocking on the door of nine-second elapsed times in the quarter-mile. The car’s 4-Valve 4.6L now sports a 5.0L Boss bottom end and an extra 43 cubic inches. The engine makes 505 horsepower at the flywheel—enough power to demand a clutch upgrade for the Tremec TKO 500 five-speed.

The able Jason Carr of MV Performance (Winder, GA) can do a clutch upgrade in two and a half hours. He starts by disconnecting the shifter in preparation for transmission removal.

Disconnecting the oxygen sensors gains five to six inches of additional space for transmission removal. The remaining transmission wiring harness connections are separated, including the neutral-safety switch, back-up lights, and speedometer.

Since the exhaust system is welded together, Jason supports that back of the exhaust system with a tall jack stand and a block before he disconnects it at the headers and removes it as a single unit.

The clutch cable is detached from the clutch fork. Jason marks the driveshaft flange and pinion flange to maintain proper alignment when the driveshaft is reinstalled. Now the driveshaft can be removed.

The transmission and starter are removed. Always support the transmission when unbolting it from the engine.

The bellhousing and clutch cover assembly are removed, exposing the clutch and flywheel assembly.

The RAM billet aluminum flywheel on the left weigh 17 pounds—14 pounds less than the OE flywheel on the right. The reduced rotating weight allows the engine to rev quicker, improving vehicle acceleration and reducing ETs at the track. The RAM flywheel is SFI approved for race use, has a perfectly flat friction surface that is exactly parallel with the crankshaft flange and is balanced to within a half-ounce to reduce engine-destroying vibration.

The RAM Powergrip clutch assembly on the right includes a diaphragm style pressure plate that provides up to 30 percent more clamping force than the stock clutch on the left, yet maintains a light pedal feel that’s close to OEM.

The flywheel and clutch disc are installed together. The Powergrip clutch disc has more aggressive friction materials to handle the increased loads high output engines place on the clutch. The Powergrip clutch setup can handle up to 550 horsepower.

The pressure plate is installed next. Note the alignment tool that inserts through the splines of the clutch disc and engages in the end of the crankshaft. The centers the disc in the clutch assembly, preventing misalignment as the pressure plate is being bolted to the flywheel.

The Powergrip clutch set comes with a new throw-out bearing. When adjusting the bearing, aim for around a quarter-inch of free play between the bearing and clutch fingers.

The QuickTime bellhousing is certified for all drag racing applications. It has a steel cone that is spun, not rolled or stamped. That makes the bellhousing parallel and centered to the crankshaft centerline within .003 inches. That dimensional accuracy means less drivetrain wear. The SFI-approved bellhousing accommodates the TKO 500 transmission as well as T5 and Tremec 3550 five-speeds.

The transmission and starter are reinstalled. A yoke is inserted in the rear of the transmission to help align the input shaft with the clutch splines as the transmission is raised into position.

The clutch fork is moved forward and the cable attached. Clutch free play is regulated at the firewall adjuster.

The driveshaft and exhaust are reinstalled and all electrical connections on the transmission wiring harness are plugged in. Like most modern performance cars, the Mach I has a traction control system. Some traction control systems apply the brakes while others retard the ignition, both of which can affect clutch performance at the track. Always disable the system at the strip to eliminate the risk of overloading the clutch. That not only affects clutch engagement, it can also drastically shorten clutch life. Gary Winter's Mach I now has a clutch assembly that’s ready for nine second ETs.

Parts List

RAM-98882T: Ram Powergrip Clutch Set, Ford 4.6L

RAM-2545:  Ram Billet Aluminum Flywheel, Ford 4.6L 4-Valve