67-68 Cougar 5 & 6 Speed Conversions

Category: SKU: 67-68 Cougar 5 & 6 Speed Conversions























Offers  five and six-speed conversions for
Small Block, Big Block or LS swapped Nova / Chevy II

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.


  • Increase in fuel economy with overdrive.
  • Lower RPM’s for more drive-ability and a much quieter in-car feeling. 
  • Reduce wear on your engine & drive-train parts
  • Reduce engine temperatures, promoting a longer-lasting engine.

Experience the MDL difference,

  • We extend the manufacturer’s warranty by an extra year…
    And we add a 1-year grace period

  • We offer best-in-the-industry customer service.
  • When you purchase a complete MDL Conversion Package you get, lifetime technical support.

T-5 Five Speed Single Overdrive Conversion

Inline Six-cylinder conversions

By 1967, Ford settled on the 3.03 three-speed with the wide pattern “Toploader” pattern.  The three-speed was budget-minded and were great in their day,  Fast forward today, these same transmissions are worn out are in the need of replacement.  The answer is a Tremec T-5 five-speed with an overdrive.  This allows the Cougar to travel comfortably at highway speed at the mid 2,000 rpm range.  Installing a T-5 into a classic Cougar is easy.  Using most of the three-speed parts like the bellhousing, flywheel, and clutch linkage, all that is needed is a new conversion clutch, adapter plate, T-5, crossmember, and a few other supporting parts.
No tunnel modifications are needed and the shifter location is retained.

If there are 2 starter bolts this means the flywheel is a 136 tooth with a 9″.  MDL has the T-5 adapter plate that to make this conversion easy.

OK, your classic Cougar is equipped with an automatic.  MDL has a complete conversion package to make this easy.
Our T-5 conversion kit includes hard-to-find items like a new inline six-cylinder flywheel, conversion clutch, reproduction easy to install clutch pedal, to the correct slip yoke for ready to bolt in driveshaft and everything in between.

V8 Conversions

Manual to Five Speed

Six bolt 289/302/5.0L equipped

Mid-year 1966 released the six-bolt blocks that carried through 302 and 5.0L HO of the ’90s.  With this change comes the wide pattern “Toploader” four-speed.  Modern Driveline’s adapter MD-401-2102 bolts to the bellhousing to allow the Fox-body T5 to bolt right up using all the stock clutch linkage.   Another option to installing a T-5 behind a six-bolt block is the fox body T-5 bellhousing.  With this bellhousing you don’t need an adapter plated and you can use a 157 tooth flywheel from the 3,4 speed.

With a T5 bellhousing you have three choices of clutch release. Stock mechanical linkage, cable, or hydraulic.

Mechanical linkage
T5 bellhousing is designed for cable release and is deeper.  To install and use a mechanical fork a fulcrum kit is required to mount the fork.  The kit has a spacer to keep the fork in the same location.  MDL can pre-drill the mounting holes for you with our fixture to ensure the mounting hole location is correct.

Cable clutch release
Since T5 bellhousing is designed for a cable release, a matching fork is required. It is important to know the 3 and 4-speed mechanical release clutches can no longer be used as it will be too tall.  MDL offers cable release clutches for 10″ long pattern as well as 10.4″ Metric bolt patterns.  The pressure plate lever height is lower and the release is faster.  To use the stock clutch pedal, MDL engineered a cable kit that bolts to the 67-68 Cougar pedal and comes complete with a firewall plate, custom double adjustable cable. The cable is routed around the exhaust system, down along the oil pan to the fork

69-70 Mustang/Cougar Clutch Cable Kit


Hydraulic 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 a 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 the back of the bellhousing pushing the fork forward. Our hydraulic system provides the most exhaust clearance while providing the softest pedal effect.

Here’s How… To Get A light Clutch Pedal with MDL’s LF-Series Hydraulic clutch System

If you are undecided as to which clutch release system is right for you, we can help you through the process of what right for you.

TKX Five Speed Single Overdrive Conversion up to 750hp



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.


From the still photos below, you can see the clearance you can expect with a stock cross-member & mount.



Click here to read more about the TKX



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

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-6773M-CMTKO 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 brack cable.


T-56 Magnum Six-Speed Double Overdrive Conversion

Magnum Six-speed is the top of the heap when it comes to manual overdrive transmission with its brute strength of 700ft/lbs. torque and two overdrive ratios.  In order to fit a Magnum in a 67-68 Cougar the tunnel has to be enlarged, once this is accomplished, the sky is the limit.  The T-56 Magnum can be bolted behind just about any power plant you can dream up.  From a SBF to a Big block or Module Coyote, the Magnum Six-speed with handle high loads down the strip or just pro-touring the open road.  Our conversion package is very complete with many choices to custom tailor the six-speed to meet your needs.  With the Six-speed we highly recommend our LF series hydraulic clutch release for a light soft-pedal that provides lots of header clearance.  In just 15-20 Minutes we can build you a detailed custom quote for you to review.

FORD Tremec T56 Magnum 6-Speed Transmission TUET11010 2.66 FIRST .80/.63 OD

Automatic or full conversion packages

Modern Driveline has perfected the automatic to five-speed conversion.  When you contact us we will ask you a shortlist of questions to better understand your needs and wants. Using our complete line of products, we can offer you everything you need to remove an automatic or completely replace the stock 3 or 4-speed gearbox.  If your project demands everything from scratch, we’ve got you covered.

When removing an automatic, nothing remains.  Our automatic kits provide everything from the back of the block to the second u-joint.  It is important to know which balance crank is installed in your motor.  289/302 up to 1980 from the factory were 28 oz imbalanced.  All 5.0L from 81-95 were 50oz imbalanced unless the crank has been changed.  Today there are many that are building zero-balanced SBF like Ford Racing.
Let us know what you are planning to run.  We will suggest the right clutch to run based on your horsepower and driving style.
In most cases, we can have a detailed quote prepared for you in under 15-20 minutes.

Converting from Auto to 5-speed or If you just want more driveability from your manual transmission mustang or want to make it more modern with a 5 or 6 speed we can help with that too.

Cool Article on a very Rare BOSS 429 cougar

MDL 5 & 6 Speed Conversions are TAILORED to your needs
With many or all of the following:

TREMEC 5 or 6-Speed Transmission with Shifter


67-68 Cougar 5 & 6 Speed Conversions are as complete as possible.
With MDL you get ALL the components you need where competitors’ packages provide only the basics.
When comparing costs be sure you are comparing apples to apples on the contents, quality & after the order service

Click or call for a customized quote for your Requirements.