Overdrive is nothing new. Before the high-winding, open-highway experiences of the ´60s, when 60 mph meant 2,800 rpm, we were decidedly efficient. There were three-speed transmissions with either electrically or manually triggered overdrive units that dropped the cruise rpm considerably.
Overdrive lowered the engine's final-drive rpm for less wear and tear, plus improved fuel economy. When the 23 cents-a-gallon excesses of the ´60s came along, we weren't concerned about those higher cruising revs. Then came OPEC in 1973-´74. Fuel prices doubled. So did gas lines and tempers. But we were still filling our tanks with foreign crude as quickly as they could pump it. Then came OPEC II in 1979. Gas lines again. Still-higher fuel prices. And a hard reality that would lead us back to Overdrive.
Beginning in 1983, Ford began installing five-speed manual transmissions in Mustangs. It was a mid-year option that changed the way we thought about cruising. At first, engine revs around 2,000 rpm at 60 mph felt funny. Ultimately, we adjusted to, and came to understand, the benefits of Overdrive. In Overdrive, newer Mustangs were achieving 20-25 mpg highway figures. With the advent of electronic fuel injection in 1986, 25-30 mpg from a V-8 Mustang was not uncommon.
In the early ´90s, owners of earlier Mustangs discovered the Borg-Warner T5 transmission's perfect fit for their vintage cars. With a conversion kit from California Pony Cars, the T5 slips right into a vintage Mustang over a weekend. Fit the five-speed gearbox in place and the shifter protrudes through a classic Mustang's shifter opening without cutting. When you get right down to it, a T5 swap is one of the easiest swaps you can accomplish with a classic Mustang.
This is the Borg-Warner T5...
This is the Borg-Warner T5 five-speed transmission. When the roller-tappet 5.0 engine was introduced in the Mustang, it came with the World Class T5 designed to handle the 5.0’s increased torque and horsepower. Make sure you’re getting a World Class T5. Two types of World Class T5s are available--M-7003-A with a 2.95:1 First gear and max torque of 305 lb-ft, and E6ZR-7003-FB with a 3.35:1 First gear, which can take less torque at 275 lb-ft. Used, these guys fetch between $400 and $600. New from Ford Racing Performance Parts, and available from many Mustang & Fords' advertisers, they're around $1,500. If you're buying a used box, open it up for a look inside. Rebuilding costs can be expensive.
This is California Pony Car's...
This is California Pony Car's bellhousing setup for Kits B and D (see the sidebar below) with the early model bellhousing, dust shield, and adapter plate.
What makes the late-model...
What makes the late-model Mustang bellhousing different is that it's a cable-style clutch linkage. The cable pulls on the clutch fork instead of pushing like the early bellcranking type. This puts the fork pivot at the end of the fork instead of near the opening. The cable routes through this dog ear on the left-hand side of the bellhousing.
This is the modified California...
This is the modified California Pony Cars' early model bellhousing. Note the modified holes (arrows) for the adapter plate.
Two types of clutch pivots...
Two types of clutch pivots were used in early model bellhousings. On the left is the ´65-´67 style, which retains the clutch fork with a wire. On the right is the ´68-up, which retains the clutch fork via a steel "tongue."
The original bellcrank-style...
The original bellcrank-style clutch linkage available from California Pony Cars is designed to handle heavier clutch-plate loads. However, fit your steed with a Centerforce clutch and say good-bye to clutch-pedal effort and linkage fatigue.
Transmission crossmembers...
Transmission crossmembers from California Pony Cars differ from ´65-´66 and ´67-´70. On top is the ´65-´66 crossmember with the parking brake bracket. Below is the ´67-´70 type without the bracket.
This is the parking brake...
This is the parking brake bracket and transmission crossmember for ´65-´66 Mustangs.
The Borg-Warner T5 takes the...
The Borg-Warner T5 takes the shorter yoke shown, available in each of the kits from California Pony Cars.
Mustangs Plus can set you...
Mustangs Plus can set you up with a correct-length driveshaft for your T5 conversion. Allow yoke travel of 1-1/2 inches, then measure from U-joint to U-joint between the transmission and rearend to obtain the driveshaft length.
California Pony Cars crowns...
California Pony Cars crowns the T5 swap with this shifter handle that looks like a vintage Mustang's four-speed handle topped with a five-speed knob. Nice touch.