TECH GUIDE: Swap from Automatic to TREMEC TKO with small block
Our TREMEC TKO small-block conversions are much like the T5 swap. We start with a cable operated 1995 351w Mustang Cobra R model bellhousing.
This same bell housing or scatter shield can be used behind any six-bolt 289/302/351 block.
The Modern Driveline clutch cable kit or hydraulic kit allows the stock early Mustang, Cougar and Falcon clutch pedals to take advantage of the modern bellhousing or scatter shield. The cable kit or hydraulic kit bolts to the stock clutch pedal in no time at all.

TREMEC TKO 5-speed performance overdrive manual transmission.
Standard height or low profile
TREMEC TKO’s can be installed into 65-66 Mustangs but requires raising the tunnel 1.5″ to make room for the taller main case. If the transmission tunnel is not raised the transmission driveline is greatly effected which will induce a vibration problem on de-acceleration. However, with the optional low profile TKO, this issue is resolved and the TKO can fit into many of the vintage cars which came with small tunnels.
1967 to 1973 Mustangs have a large enough transmission tunnel, so no modifications are necessary.
Clutches and flywheels
Using the R model bell housing with a clutch cable kit or hydraulics will require using a diaphragm pressure plate found in late model Mustangs. 302 engines dated 1981 and earlier will need a 157 tooth 28oz imbalance flywheel, as do the 289 and 351 blocks, regardless of year. 302/5.0L engines will need a 157 tooth 50oz imbalance flywheel or otherwise know as a 5.0L flywheel. We offer flywheels with fixed and removable counterweights depending on the need. Removable weights are handy when there are plans to swap motors in the future that require different counterweights.
Crossmember
Since the TKO transmission mounting point is further back than stock 3-4 speeds, a TKO cross member is needed for vintage cars.
The cross member is designed for use with the stock early style rubber transmission mount, so don’t make the mistake and purchase a late model T-5 transmission mount as it will not work.
Shifter
The TKO shifter has two threaded holes to mount almost any kind of shift lever desired. We offer both a stock like appearance shift lever, ball and boot, and the Hurst classic style. For those who like the Hurst look of the ’60s, there are several chrome levers to choose from. Hurst also offers five-speed pattern shift balls in white and black or T-handles found in vintage cars.
Speedometer
Be sure to save the automatic transmission speedometer cable, as it can be reused. You will, however, need to install a speedometer driven gear, which is available in a variety of tooth counts to match your differential gear and tire combinations. Installing the new speedometer driven gear is simple, it requires removing the c-clip and pulling the old gear off and sliding the new one on.
Neutral safety switch
Automatics have a neutral safety switch so that the car can only be started in park or neutral. Manual transmissions don’t need the switch, which 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 safety switch. Splice two of these wires together and you’ve bypassed the neutral switch.
Starters
The starters from early 289-302 Fords with automatic transmissions work just fine. The starter from any ’85-’95 Mustang 5.0, auto or manual, will work. When header clearance is an issue, 1992-95 5.0L Mustangs use a high-torque starter which will run about $130.
Additional info…
- Swap from automatic to T5 with a small block
- Conversion of manual transmission-equipped cars
- Conversion from automatic to TREMEC TKO with a big block
- Classic Mustang Transmission T5 Swap
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