Is there a such thing as adding on OD to tail shaft end of 727?

[1969chargerrtse]

Subject says it all.  I searched but can't find anything.  I heard you can add an Overdrive unit to the rear of the trani and you just need to shorten the drive shaft.  Anyone know anything about this, and links for a supplier?  thanks.

[gordo1968charger]

gear vendors?

[SnoPro440]

      

http://gearvendors.com/hrdodge3s.html

[gtx6970]

Subject says it all.  I searched but can't find anything.  I heard you can add an Overdrive unit to the rear of the trani and you just need to shorten the drive shaft.  Anyone know anything about this, and links for a supplier?  thanks.

as in using OE factory parts ?

Will it bolt on ? yes,
But will it work ? Not a chance . internal lubrication and the clutch apply circuits are all wrong, as well as the valve bodies are completly different between the 2 styles.