Bill, not trying to rock the boat on you, but
I don't think the Warner T85 was used in Chevrolets as original factory equipment.
I believe Ford and AMC were the only manufacturers to add an overdrive to the T85, which I think was called the T85N. The most common trucks to find the OD unit in were the '65 to '71 Ford trucks. I found one in a '67 or so Ford at the junkyard, but when I went back to pull it out it was gone!
There was a good article on this transmission in Hemmings a few months ago...I'll try to find it.
