Re: '69 TH-350 speedometer cable length
This is a very late response to this post, but maybe someone will find it useful. Seems there is nothing definitive out there.
My '69 Malibu has a 350 / TH400. The speedometer needle would fluctuate ±5 mph, and I found the speedometer cable was laying on the exhaust and the casing had burned through. The old cable measured ~58" and was routed from the transmission, over the exhaust, on top of the driver side frame rail, back toward the middle and up through the firewall. The 3rd party stores had various lengths, but nothing close to 58". I tried the GM dealer. Nothing. Autozone had a 47" that I thought would allow me to keep the cable away from the exhaust, but it was about 3" too short. The 61" (CA-3005)worked fine. I routed it a little shorter under the car, added a loop bracket to the frame (existing hole) and took up the slack with routing behind the dash. My understanding is the manual missions have the cable out the passenger side and need the longer cable as a result. Maybe the 120". Installation is easy. Speedometer needle no longer fluctuates.