Modified Mustangs & FordsHow To Drivetrain
Simple Five-Speed Swap for Your 1971-1973 Mustang
Take Five! - Modern Driveline’s Five-Speed conversion package for ’71-’73 Mustangs can be swapped in a weekend
Classic Mustang five-speed conversions are nothing new, but how we do them is getting better all the time. There are piecemeal conversion kits and there are user-friendly conversion kits that make getting into five-speed overdrive technology an easy weekend task, getting you back on the road by Monday morning. Modern Driveline offers you a complete one-stop Tremec five-speed conversion package (T5 or TKO) for the '71-'73 small-block or big-block Mustang or Cougar complete with all hardware, crossmember, bellhousing, clutch and flywheel, related components, and transmission. It has everything you need and eliminates the stuff you don't need. What's more, Modern Driveline allows you to order “a la carte” meaning if you already have the part, you won't need it for your conversion.
If you're driving a '71-'73 Mustang or Cougar with a three- or four-speed stick, or even an FMX, C4, or C6, your first order of business is rear axle gearing. If your Mustang or Cougar has a 2.79:1, 3.00:1, or 3.25:1 axle ratio, cruise performance won't be what it could be with 3.50:1, 3.73:1, or 3.91:1 cogs. With 3.50:1 gearing, you can expect 2,000 rpm at 70 mph on average depending on tire diameter.
We're working with the Rebuilding Generations Mustang convertible project car, which is a solid commitment to young and old working together in an effort to pass the torch to a new generation of car enthusiasts. We older folks can impart valuable information to young people while learning something new from fresh eyes who can spot the need for improvement perhaps showing us a better way. Rebuilding Generations is a program founded by Kevin Keep that was brought about by the guys at My Deals, LLC to help bridge the gap between the younger and older generations. The program's goal is to provide opportunities that will help build a mutual level of respect and appreciation of the knowledge and wisdom both generations have to offer each other.
The first Rebuilding Generations project is a '71 Mustang Convertible provided by Ryan Hoffins, marketing manager at Optima Batteries. On its website at www.rebuildinggenerations.com, you can see videos, photos, and interviews on the progression of this Mustang throughout the restoration process. This car was rolled out for the first time at the 2013 SEMA Show in Las Vegas.
01. This is the time proven Tremec World Class T5 five-speed transmission new from Modern Driveline with 2.95:1 First Gear and 0.63 overdrive. Because Modern Driveline is a Tremec Elite Dealer, you’re getting a new T5 right from Tremec’s production line. And when your T5 needs service, Modern Driveline can help with trained professional tech support and service. Each T5 is thoroughly inspected prior to shipment.
02. Modern Driveline offers a nice line of cast aluminum and QuickTime formed steel bellhousings for a wide variety of Ford applications.
03. Bruce Couture of Modern Driveline stresses the use of pilot bearings instead of bushings for smooth operation and durability. Though more expensive, pilot bearings are money well spent for longevity and smooth shifts.
04. The T5 and cable style bellhousing call for this aluminum engine/bell separator plate, which is a Ford part available from Modern Driveline.
05. Bruce Couture of Modern Driveline explains the fundamentals of clutch design and installation to Rebuild Generations, which is building the ’71 Mustang convertible in this article. Our subject vehicle is a 302ci small-block ride ready for the T5’s great efficiency. The car has been fitted with a Strange 9-inch rearend with 3.55:1 Traction Lok, which makes it ideal for the Tremec’s 0.62:1 overdrive.
06. Because we’re running a 302 V-8, Bruce has chosen a steel flywheel with a 28-ounce offset balance for our Superior diaphragm-style clutch.
07. Flywheel bolts on small-block Fords thread through the crank flange and right into the crankcase. Use Teflon sealer on bolt threads and keep oil inside where it belongs.
08. Flywheel bolts are torqued crisscross in one-third values to a total of 80 lb-ft.
09. This is something Bruce does on all of his clutch and flywheel installations. He checks the bellhousing to ensure it is perfectly centered on the crankshaft. Not all bellhousings are drilled perfectly, which can cause unacceptable side loads on transmission input shafts.
10. We’re installing a Superior diaphragm clutch from Modern Driveline. Superior Clutches handcrafts each clutch one at a time for Modern Driveline. If you opt for a Kevlar clutch disc, be confident in knowing Superior’s are 100-percent Kevlar and can withstand a lot of abuse. We’re installing an organic clutch disc for what will basically be a weekend cruiser. Pressure plate contact surface is cleaned with a high-evap’ solvent and a tack rag.
11. The Superior organic clutch disc is installed using the alignment tool provided. Loctite is used on Grade 8 pressure plate bolts, which are torqued in a crisscross pattern in one-third values to 35 lb-ft.
12. Bruce Couture offers a couple of suggestions for clutch alignment tools. Shown here are two plastic clutch alignment tools. One fine tooth and the other coarse tooth for different input shaft types. Bruce has taken a used up input shaft and cut it for use as a clutch alignment tool. He tells us the steel shaft works best if you can find one.
13. Because we’re going with a cable clutch conversion kit from Modern Driveline, we’ve opted for a cable-style bell and fork. Pivot ball has been lubed and the release bearing is lined up for transmission installation. Release bearing needs molybdenum grease around the inside, however, never use too much. Just a thin film of grease on these parts because you don’t want the excess caught up between pressure plate, disc, and flywheel.
14. Bellhousing is torqued tight using a 5⁄8-inch socket and extension.
15. This is how your Tremec T5 from Modern Driveline will arrive. Each T5 is thoroughly inspected prior to shipment to ensure integrity.
16. Our Tremec T-5 is secured on a transmission jack and is ready for installation. The T5 is light enough to install on your back underneath the car though this is not recommended. We have the good fortune of Modern Driveline’s lift and transmission jack along with Bruce’s experience.