TKX Five Speed Single Overdrive Conversion up to 750hp

We put a New Tremec TKX in a 1966 Mustang.
The tunnel support was moved back 2-3/4″ then reattached to the floorplan & tunnel.
Our crossmember & mount were used on the TKX as you can see it maintains the angle requires and we have great clearances. We also have about 5/8″ space between the trans top & tunnel for driveline angle adjustment.
This is an added bonus to the already impressive rating of 600ft/lb of Torque & the new addition of triple cone synchros in the TKX gives you smooth shifting up to 8000 RPM.

For higher torque applications or you’re a ‘spirited driver,’ the TKX series five-speed is the latest offering from Tremec, check out these stats.

Rated for 600lb/ft of torque, will support shifting up to 8000rpm thanks to triple cone hybrid sintered synchronizers that the Tremec T56 Magnums have to make your driving experience the best.

The new end loading design makes for a stronger case with a new sleeker profile, eliminating top covers, that would have restricted room in the tunnel.

Click here to read more about the TKX

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Above you can see the differences between the TKO & TKX cases

Much like the TKO the floor support has to be moved back about 2-3/4″ over the narrow section tail shaft housing to retain the stock drive angle.
The TKX offers a little more adjustment approx. 5/8″ at the tail shaft vertically for the driveline angle. Perfect for Pro-Streeters who love to tuck the rear suspension up into their ride.

This can be done by removing the factory spot welds and relocate the support back.
A great addition to the install is the MDL Crossmember item# MD-6566M-CMT5 and a new mount, this will maintain the transmission angle as well as providing superior clearance for exhaust and a locating arm for your emergency brake cable.


65-66 Mustang 5 & 6-Speed Conversions from Modern DriveLine

We offer the most complete line of five and six-speed conversions for Mustangs.
Our line of products offers simple ways to upgrade your 3 or 4 speed to a Tremec five-speed or a complete automatic to five or six-speed overdrive, we have you covered.

Experience the MDL difference

  • Experience the MDL Difference,
    • We extend Tremec’s factory warranty by an extra year.
      And we add a 1-year grace period.
    • We offer the best in the industry customer service.
    • When you purchase a complete MDL Conversion Package you get, lifetime technical support.


If your Mustang is a manual shift, this conversion will cost less than the automatic conversion. Using many of the OEM parts, like the bellhousing with an adapter, flywheel, clutch, and mechanical clutch linkage.
MDL has a complete line of in-house hand-assembled clutches for various HP ratings, cast, and Light Billet Steel flywheels should you need a replacement or plan to increase your HP.
For those who want an effortless pedal feel or are challenged by a heavy pedal, MDL offers you an internal hydraulic upgrade.
If you are running a fair amount of power or run your Mustang in motor sporting events, the QuickTime scatter shield is available. The Quick Time bell-housing is built to use either the stock clutch linkage, clutch cable, internal T/O, or external hydraulic release to provide the smoothest pedal feel and give you the most header clearance.

Check out our HOW TO page, just click this link

Click here to see our Frequently Asked TECH-Questions/Answers page

We also Have OIL COOLERS   click this link to find out more





We offer complete conversion packages for Ford & GM featuring the NEW TKX


Cable clutch release
Since T-5, TKO, and Quick Time bell-housings are designed for a cable release, a matching fork is required. It is important to know the 3 or 4-speed mechanical release “clutch” can no longer be used as it will be too tall.
MDL offers cable release clutches for 10″ long pattern as well as the 10.4″ Metric bolt patterns.  The pressure plate lever height is lower and the release is faster.
To use the stock clutch pedal, MDL has engineered a cable kit that mates with the stock 65-66 Mustang pedal and comes complete with a firewall plate, custom double adjustable cable the is routed around the exhaust system.


Hydraulic clutch release –
MDL developed a complete line of hydraulic clutch release systems we call our LF (Light Foot) Series.
The master cylinder mounts on the firewall using our mechanical linkage that connects to the stock clutch pedal.  The linkage provides proper leverage and control while providing design flexibility.
Using the T-5 and cable fork, our external slave cylinder mounts to the back of the bell-housing fork opening, pushing the fork forward. Our hydraulic system gives you the most exhaust clearance while providing the softest pedal effort.