Last year I went through an exercise in determining the correct driven gear to make my speedo read correctly. I noticed back then that the inner part of the speedo cable itself would move what I thought was excessively in the shielded casing - at least an inch or so in and out. I didn't think much of it until I took the car out yesterday and watched the speedo needle droop and droop until it stopped working entirely. So I figure I should have replaced the cable last year - I'm guessing the inner piece should not slide in and out. Anyway, it seems harder to find the right length cable to order than it will be to replace it. For a '70 Cutlass with an M20, I see many listed cable lengths - 56-3/4", 61", 63", 66", 68", and 80". All insist they are "factory replacement length". I've done a search here and cant find a thread that discusses a '70 speedo cable length. Does anyone know what I should be ordering as a replacement? Mine is the clip on connector, not threaded at the speedo. Thanks

 

Pull the inner cable out and measure it. If broken may have to take it out both ends. Also I think a good speedometer shop can make one.

 

I suppose it could have broken, that wasn't something that occurred to me. I was hoping, however, to just take the car up on the jacks once and have this issue done with, the reason I was asking if there was a common length that was documented somewhere. Order it, crawl under, and swap it out at one sitting... The closest speedo shop near me is about 3 hours away outside Detroit, so buying new is probably the way to go.

 

Hey Bob, I don’t know the answer to your question about the length. I see everything from 63-78 inches being listed as correct on eBay. Inline has one listed as being correct but don’t list the length. They are usually pretty good in my experience.




https://www.ebay.com/itm/69-70-71-72...640c%7Ciid%3A1

 

I appreciate the link - I need the 4-speed model, and after digging through all my manuals and the ASM, it seems that the MotorCity reproduction is the only one out there with the sleeve wrapped around it and a new grommet for the firewall. So I went with them. I still never found a site that showed or listed the cable length, though with the connection on the passenger side, I'm inclined to think it's the 80" I saw in a few locations. I will absolutely measure this one when it comes in and I will measure the one I take out of the car (assuming I can confirm it's original).