speedometer cable

I just got my new autometer Ultralite 2 gauges and they are really nice. Everything hooked up nice until I got to the speedometer. I have a thread on sending unit and a push in style cable on the transmission. I called Thunder Road and they said they had never heard of anything like that, I...

Hey guys, Cutting to the chase - I've picked up that standard squeak behind the dash from my speedo cable so I'm looking to replace it for my 73 hatchback (TH350). Any insight into the correct cable length? Local parts places seem to sell 40" and 80", neither of which I believe are stock...