'69 SS speedometer head has started fluctuating and making noise in the head area between 15-25 MPH.. had intentions of removing the cable off the back to remove the head and make an inspection of the unit,, but I can't figger out how to get the blanged cable off of the head. it's not threaded-in; I can get to it with channel locks and turn it, but it won't come out... help ??

There is simply a tab that you push and the cable should come right out. I can't really explain what the "tab" looks like -it is kind of spring loaded and goes around the cable. Just feel around the base of where the cable attaches to the speedo and you sould feel it. Once you push down on the tab the cable should come right out. Perhaps someone could post some pics (???)

ya kausboy,, I'm familiar with that type tab you're talking about, but mine doesn't have anything like that.. for all standard reasoning, it looks-like it's just "pushed" up into the head.. but it sure won't just "push-out"..
I don't have any slack in the cable housing what-so-ever, and that's not helping the process either; however, I can rotate the cable housing with the pliers.....

Disconnect the cable from the transmission to get some slack. You should then be able to pull the instrument cluster out enough to get to that cable connection on the back of the speedometer.

More than likely all your cable needs is some light lithumn grease , It could be possible to remove he cable from below at the transmission , IF you dont have the button at the speedo head,,, Worth a try, take nut loose at the trans and see if cable is removable. If cable is dry and I bet is it, take out and roll up in small circle, apply a coating of Lubplate grease, work into wire well and reinstall. Thats a IF the button on the cable is not present.

hmmm,,, never tried it that way, but it could work I guess. could probably get the cable re-inserted by rotating and twisting it back in.. I was thinking maybe the problem is more in the head assembly, than the cable, because the needle steadies and no noise beyond a 25 MPH reading.
Farm Boy: I can get to it just fine,,, it's more-like the cable housing is mechanically pressed-on (like as in a hydraulic hose assembly) or something,
except the housing rotates on what would-be a threaded mount .... weird.
wondering if I have an aftermarket speedo of some type where you buy the entire assembly, cable and all, and it's not separable ??
as you say, I might be just as well-off taking the trans connector off and pulling the whole schebang out as a unit..
thanks for the ideas guys