[Tigers] flexplate motor to flywheel

[Thomas Witt]

Steve,

This is from http://www.fordmuscle.com/archives/2000/09/t5swap/index2.php 
( full story)

Clutch and Flywheel - 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.

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.

Tom