Larry, Sorry for not replying sooner. I don't know what years to look for, but the Borg Warner overdrive was an add on kit for 3 speed tranmissions from the 30's to the 60's. It used an electric solenoid to actuate a set of planetaries for a gear reduction.
I spotted a GM model at the scrap yard awhile back. You may have scrounge around some swapmeets to find one, but they are out there.
Try this link:
http://www.hydratech.com/pctc/Public_Documents/bwwiring.pdf
