Speedo Issue

304-dude wrote: As a note... my 71 had a cracked speedo head. Plastic push on. It did not effect connection, but it allowed me to remove the head and pull out the spring wire from the speedo head end. Yes it was squared off and probably made it the only way to be removed, from the head side of the cable. Since the speedo is enclosed at the receiving end, it keeps the cable from being pushed up. I would expect if the tranny speedo gear is inclosed, both head and bottom cannot go anywhere, if loose and free to be pulled through the sheath. Though I don't know how easy it is to remove the speedo head from the screw on types.

That was in part not to keep it from escaping, but to keep the cable from moving at all. It more or less trapped the cable so it couldn't screw itself up or down. It's not a matter of it being "enclosed that the receiving end"
You must have some end play in the cable to allow for shrinkage and expansion and slight differences in tolerances, but the shoulder prevents almost all end-play, etc. It keeps it quieter as well as the top end is trapped via that shoulder so it can't SLAP in the housing. 

The screw-on types are SIMPLE - IF IF IF you can get TO them. I like either, it's not the fact it's screw-on or clip-on, it's can you even touch the cable?
I have found Javelins to be hundreds of times easier to deal with dash-wise than say, Eagle, Spirit, etc. 
Eagle dash work SUCKS - and that's only because I can't use words to say how I REALLY feel about accessing the back of the cluster on Eagle. I'm dead serious in that if Ken (pit crew) doesn't like Javelin dash work I will honestly do five of his if he'll deal with my Eagle dash for me.
You can't even touch the cable on an Eagle - at least like mine - until you half-way remove the cluster and pull it forward and to do that you remove the package tray, and several other parts, then PRY brittle plastic out of the clips and lean the cluster forward and pray things don't break and crack. This is why I have several clusters and boxes of dash parts for Eagle. 

When one lubes the speedo cable and afterwards finds that the needle still jumps around; it's time to go to plan B. There is a brass bushing inside the speedo head that will need to be replaced. Pull the speedo and take it to a speedo shop. It's only a few bucks if the speedo head is out of the dash.