Michael Galimi
January 7, 2011
Photos By: Courtesy Of Quick Time Performance Parts

The gear ratios are also extremely different. Getrag comes with the following-3.66:1 (First), 2.43:1 (Second), 1.69:1 (Third), 1.32:1 (Fourth), 1:1 (Fifth), and 0.65:1 (Sixth/Overdrive). In comparison, the Tremec Magnum comes with two different gear ratio options-2.66:1 (First), 1.78:1 (Second), 1.30:1 (Third), 1.00:1 (Fourth), and two Overdrive gears 0.80:1 (Fifth) and 0.63:1 (Sixth); the other S197 Magnum offers-2.97:1 (First), 2.10:1 (Second), 1.46:1 (Third), 1.00:1 (Fourth), 0.74:1 (Fifth), and 0.50:1 (Sixth). We installed the 2.97:1 version in the JPC Racing test vehicle.

"I ran a pro-shifted Tremec TKO 600 in my '11 Mustang for the MM&FF 5.0L Shootout because we didn't have the T56 Magnum yet. We offer that conversion as well for the real hardcore racers out there," said Burcham. "Now that Tremec sent us a S197 Magnum, it's the transmission that will be in my car full-time. It might be hard to believe, but I do drive the car nearly everyday, and I need a reliable transmission that I can drive on the street. The pro-shifted box was a little too much, even for me," laughed Burcham.

Final pricing for the kit hadn't been set when we went to press as JPC Racing was waiting for the production release of the transmission from Tremec. The S197-spec T56 Magnum should be available shortly after the release of this issue.

T56 Magnum versus TR6060

"The T56 Magnum is essentially an aftermarket version of the TR-6060, which was first introduced in the Shelby GT500," said Nate Tovey of Tremec. The upgraded transmission had enough aftermarket-specific changes that the company felt it needed a new name, so it adopted the T56 Magnum moniker-a nod to its original T56 six-speed roots. Some of the major differences between the Magnum and TR-6060 include bearing upgrades, friction materials (carbon content) on the synchronizer blocker rings, dual speedometer pick-ups (electronic only for the S197-spec), dual cross-member mount threads, longer input shaft splines for multi-disc clutches, and hydraulic and mechanical release support systems.

A switch to this transmission does require a 26-spline clutch disc, two-bolt crossmember, and a one-piece driveshaft. This article outlines the '11 spec kit from JPC Racing but the company will also offer all the parts and pieces required for a '05-'10 conversion to the T56 Magnum.

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McLeod RST Twin Disc Clutch

Swapping to the Tremec T56 Magnum probably means that your Mustang is producing a good amount of power thanks to forced induction, nitrous, and/or serious engine modifications. That means you are going to need a good clutch between the engine and T56 Magnum to endure the abuse. The JPC Racing kit is offered with two clutch options, the McLeod Racing RST or RXT. Both feature twin-disc setups and offer a reasonable clutch pedal feel-meaning you don't have to take steroids in order to push down the clutch pedal.

Lee Kilcoyne of McLeod Racing offered this explanation, "The RST has organic discs rated to 800 flywheel horsepower, and the RXT has metallic discs rated to 1,000 flywheel horsepower." Essentially you have to figure out which clutch applies to your application and make the choice. As far as driveability, Burcham told us he has driven both styles and there isn't much of a difference on the street. He reported no chatter with either clutch, which is present in some other twin-disc setups, and pedal feel was great.

Kilcoyne did offer this advice when choosing between the RST and RXT: "It matters how much time the car will spend on the track, and the individual's driving skill at the track and racing. If they only need a RST but they're going to the track often, then they might want to upgrade to the RXT. If they have an oops at the track and glaze the discs due to poor burnout and such, then the unit has to be pulled to be fixed. If they have the RXT discs then the unit will recover and continue to function as designed."

If you are asking about it, why not just get the RXT? The answer is simple. The RXT retails for more money than RST. JPC offers the RST at $659; the RXT comes in at $859.