1962 RPO 685A or 685B 4-speed tranny
My '62 has engine RPO 396 with a 4-speed. Was RPO 685B, the close ratio tranny, standard on the 340 and 360 horse motors with a 4-speed, or was it an option? If it was an option, how does one tell the difference between RPO 685A and 685B?
-
-
Re: 1962 RPO 685A or 685B 4-speed tranny
In 1962 I believe that in Corvettes there was only 1 Borg Warner 4 speed offered as RPO685 and it was a close ratio transmission. -
Re: 1962 RPO 685A or 685B 4-speed tranny
David -
There were two different RPO 685 Borg-Warner T-10 4-speed transmissions in '62; the 250 and 300hp cars got the wide-ratio version (2.54:1 low gear) and the 340 and 360hp cars got the close-ratio version (2.20:1 low gear).
If the 1-2, 2-3, and 3-4 rpm drop is about the same, it's a close-ratio; if the 3-4 rpm drop is significantly more than either 1-2 or 2-3, it's a wide-ratio.Comment
-
Re: 1962 RPO 685A or 685B 4-speed tranny
Thank you both. I am going to assume that since the serial # on the tranny case matches my car VIN and the car came with RPO 396 that I have a close ratio. The rpm drop idea is a good secondary indicator too, John, so thanks. My next question, then, is if I get a replica window sticker, should the 4-speed RPO # read 685A or 685B? I have not seen any original window stickers in order to know whether or not there is a difference indicated or if they all just read 685.Comment
Comment