Hello,
Try posting an ad in parts wanted. I'm sure someone will have one. I would think 60-66 would work but I'm not positive. I'm not sure about converting one either. My truck is a 60 C10 and originally it had a manual transmission with a column shifter but it's automatic now. It does have the original column I think with the gear lever removed but the automatic shifter is on the floor. It looks like a 4 speed because the clutch pedal is still there too, but not functional. The work was done by the PO so I'm not sure what was involved.
Joe


54 Triumph TR2(rhd)needs total resto.
60 Apache 10 stepside shortbed
99 Excelsior Henderson