do they make such an animal? I looked and looked. I could find them for a bunch of other trans, but not a C4. I bought a el Chepo sepedo cable and was just gonna hack the end of it off, but it doesnt seem to want to go in the hole. https://www.summitracing.com/parts/atp-y856/questionsanswers#qa-display-detail I dont know if there is pressure at the hole or if i can just get a freeze plug or rubber adjustable plug and shove it in there. Thank in advance.
AFAIK speedo cable opening on Ford transmissions from at least early '60s through early '90s are all same. Incl C4, C6, T-5, AOD etc etc
here is one...... https://transmissioncenter.net/shop/ford-slip-in-style-speedometer-billet-aluminum-plug-kit/
see i saw that , it says it fits all this T stuff. I guess from the post above, thats all the C stuff too?
My money is on a GPS speedometer. I like the idea but there are areas here where you will lose signal along with all all your readings.