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T5 Swap for Early Fords (continued)

What parts are needed?
If your converting and automatic car to a manual or five speed, you'll need to round up the clutch pedal and associated parts. For early Fords this can be tough. Your best bet is to find a wrecked car which has the manual parts and take everything. Some of the smaller pieces, such as springs, bushings, z-bar and mounts are still sold through Ford or Mustang parts houses. For late model Fords using a cable operated clutch, all you need is the brake and clutch pedal assembly.

T5 Crossmember
- Regardless of whether your early Ford came equipped with an automatic or manual, you will need a conversion crossmember because the mounting pad of the T5 (and AOD) hangs much lower than other Ford transmissions. Companies such as Modern Driveline (see contacts below) sells crossmembers for early Mustangs, and possible Falcons and Fairlanes. They cost about $150. The other option, if you have access to a welder, is to make one yourself for considersably less money.

Slip Yoke and Driveshaft- The T5 requires a 28 spline slip yoke. The slip yoke from C4's, C6's will work since they are 28 spline. Most Toploaders slip yokes will work, however some came with a 25 spline output shaft so be sure to count. Fords originally with 3 and 4 speed manuals will require a slip yoke swap. Driveshaft length in early uni-body Fords will typically not require modification, however you should ensure there is 3/4" to 1.5" of space between the base of the slip yoke and the end of the tailshaft housing (not the seal!), when the car is on the ground. Distances greater than this will require a longer driveshaft, distances less than this will require shortening of your existing driveshaft.


Clutch and Flywheel - If your car is already a manual, simply use the existing clutch, flywheel, and throwout bearing. You should change the pilot bushing to the late model Mustang pilot bearing. Since you will need to remove the clutch and flywheel to install the T5 blockplate, you may as well take the opportunity to install a fresh clutch.

If your car was an automatic you will need to get a flywheel which matches the balance factor of your motor. All 289's use a 28 oz. balance factor. Early 302's up to late 1970's also used a 28 oz. factor, but after that point Ford switched to a 50 oz. balance factor. If you mix and match the flywheels (or harmonic balancers) your engine will vibrate itself to death! So be sure you only install the flywheel with the correct balance factor. A good machine shop can convert the more common late-model 50oz. flywheel to a 28oz. balance factor for around $50. The 50oz. flywheels are also drilled for the larger 10.5" diaphagm clutch, which the 28oz. flywheels must use the early style 10" three-finger clutches.

Stock 28 oz. and 50 oz. flywheels have 157 tooth ring gears measuring 13.294" outer diameter. Some 351W engines, and after market flywheels, have a larger 164 tooth ring gear which has a 14.215" outer diameter and accepts an 11" clutch. The larger clutch may not clear the inside of the T5 bellhousing.

Starter - The starter from any '85-'92 Mustang 5.0, auto or manual, will work. The '93 and up Mustangs use a high-torque starter which saves weight and space, but costs about $120 more than the standard type. The starters from early 289-302 Fords with automatic transmissions also work, however starters from manual transmission cars of this era seem to have a slightly larger mounting lip and don't fit unless you mill or grind this surface down. Your best bet is to use it as a core at the parts store.

Neutral Saftey Switch- Automatics have a neutral safety switch, so that the car can only be started in park. For a manual you do not need this, and the switch must be by-passed or the motor will not start. On early Mustangs the four-plug harness sticks out of the firewall above the master cylinder. Two of the wires control the reverse lights, the other two control the neutral saftey switch. Splice two of these wires together and you've bypassed the neutral switch. Which two wires? You'll need to use a voltmeter or take a couple guesses to find out! On other cars you can check the wiring diagrams in a shop manual, or trace the wires from the original automatic shifter. The backup lights can be made to work by connecting the other two wires to the two leads on the T5 case.

Speedometer Cable and Gear - Your existing speedo cable will work, provided it is the right length. Ford suprisingly didn't change the design of these things from car to car. You may need to re-route the cable to get it to reach the entry hole at the rear of the T5 case. You will however need to put on a T5 speedo gear, available from your Ford dealer, in a variety of tooth counts to match your differential gear and tire combo. Swapping the new gear on simply requires removing the c-clip and pulling the old gear off and sliding the new one on.

Bellhousing Modification - The T5-to-bellhousing mounting pattern is different than that of other Ford manual transmissions. This means you need to use a T5 bellhousing, with a minor modification, or you need to buy a adapter plate that sandwiches between the older (Toploader) style bellhousing and the T5. The preferred method (cheaper, easier, stronger) is to simply get a T5 bellhousing. The adapter plates are machined out of aluminum and cost $200 or more, and can result in an alignment problem. The T5 bellhousing however is about 1" deeper than the earlier Ford bellhousings (because the T5 had a 1" longer input shaft). Furthermore the T5 bellhousing is setup for a cable activated clutch fork. You can certainly keep it this way, but it will require modifying your clutch pedal to accept a clutch cable.

We opted to stick with the early-style pushrod activated clutch fork, this requires making a minor modification to the T5 bellhousing. You will need a 2"x1"x1" aluminum or steel block and also the fulcrum (the piece the clutch fork pivots on) out of your early bellhousing. Sacramento Mustang, Mustangs Unlimited, and CJPony Parts sell the spacer block, fulcrum, and bolts as a kit for approximately $40.

For early Fords with manual clutches, you'll need to install or transfer the fulcrum style clutch fork from a four speed or toploader bellhousing. Due to the longer input shaft of the T5 you need the 1" spacer block under the fulcrum. Available from Windsor Fox, Mustangs Unlimited, and others.
The hair clip shown at the top holds the fork on the fulcrum, don't leave it out!

To modify the T5 bellhousing, you need to first remove the cable activated clutchfork and fulcrum. Simply pull the clutch fork up and it will come off its clip. Then unbolt the pivot ball. The next step is to mount the mechanical style spacer and fulcrum. The fulcrum and spacer sit exactly 1" from the rectangular opening in the bellhousing. On the T5 bellhousings there is a little oval casting that sits between these two lines. The edge of the spacer basically needs to be mounted right up against this casting, but NOT on it. Mark two lines from each corner of the rectangualar opening extending to the center hole where the transmission mounts. Both these lines should be parallel to each other, and exactly straight!

Now place the spacer in between the two lines. We've determined the spacer should be one inch from the edge of the rectangular opening, up against (but not on) the oval casting mark. Mark the holes and drill. If you want to double check our measurements before drilling, you can tape fulcrum and spacer in place and attach the clutch fork. Then mount the bellhousing on your T5 and check that the clutch fork can pivot without rubbing the input shaft or the rectangular opening. Mount the fulcrum on top of the spacer and bolt it in place. (Note, the spacer kit we obtained from CJ Pony parts came with counter sunk allen bolts. We didn't want to deal with drilling countersunk holes, so we simple replaced them with standard hex-head bolts.

If you mounted the spacer in the correct spot, the hex heads will not interfere with the transmission case. Finally, you will need to hack off the tab on the bellhousing directly in line with the clutch fork opening. This tab is used to mount the clutch cable, and will interfere with the lower pushrod for the manual clutch. You only need to hack or grind off 1/2" or so off the edge, this way you still have the mount in case you ever want to convert to a cable operated clutch.

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T5 Crossmembers

The Modern Driveline crossmember is a strong piece which follows the stock shape, making for better header and exhaust clearance.

The California Pony Cars T5 crossmember serves its purpose, however the mount bracket welded to the main tube is a weakness. The member also offers less exhaust clearance.

 

Bellhousing Modification

Cable operated clutch fork (right) and converted fulcrum style clutch fork (left.)

Modifying the T5 bellhousing for the early style clutch fork requires this 1" thick spacer block under the fulcrum to make up for the longer input shaft (hence deeper bellhousing.)
Looking Stock

You can maintain the stock look by modifying the early shifter. We hacked off the 3spd/4spd lower bracked and welded on a metal tab. Drill two 3/8" holes to match the T5 shifter nub. Slip the stock boot over it and no one can tell from the inside that you've got an extra gear!






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