If you still have your torque tube in place Patricks conversion for the Saginaw will work on a 3 speed just the way it does on the 4 speed except you won't need to buy the shifter assembly.
Just disassemble the tranny, swap the mainshaft, install his custom designed torque tube tailhousing and put it back together.
I have an aquaintance that did just that to his truck so he could carry 3 people comfortably in his cab.
