It looks like I may have to remove dash panel above steering column to get at speedo cable for replacement.Whats envolved in removing entire dash? I may as well take it out,re-dye,change light bulbs,etc.I see the h.light switch must come out,2 bolts on underside of st. column,some plastic duct pc. But its all those wires that scare me.Upper dash pad has long ago been removed,and the w/shield is also gone.Help please. Mikey

With the windshield and upper dash out, you can reach down from above to release the speedo cable, so you don't need to remove the whole dash. 

If you still want to redo the dash, take off the bottom cover and unbolt the steering column and let it sag.  There are two screws on the left side of the dash panel that you get to with the door open, and two from the gauge cluster.  Bundles of wires hang from metal straps that you bend open and release.  Take the vacuum hoses off the headlight switch and mark the order they go in.  The wires will stay pretty much where they are as you unplug them, and a wiring diagram can solve any problems in getting wires back where they came from.  But it is still a lot of monkey work getting it out and back in.

Larry

 All of the wires are marked good on the back of the speedo and tach housings and for the connectors one fit in one spot...any time that I pull anything a part I take lots of digital pictures for later reference...Due to bad memory...If you move the wires on top make sure that the bulk of wires above the speedo and the tach go back on top and not fall between the back of the speedo /tach and the firewall, things fit tight.

First off thanks to all the responses to date.I cannot get at the speedo connector with lower dash in its factoty position.Do I need to loosen up all the mentioned things just to get at the connector? New cable looks like it screws into back of speedo,is there anything else holding it to speedo besides the screw on thingy at end of this new cable?

I am almost sure that the cable end with the threaded end is the tranny side  but the other end should be just a slide on end with a lip that will catch on a clip, that end goes to the speedo and the clip is just like a bent washer that you will need to push the clip toward the housing and pull the cable off. the reverse to install

Mikey,

What andrechevy said...I do them from the bottom underneath the dash...not easy.

I removed the cable between the trans and cruise servo which WAS mounted on inner fender well.I now want to put in a one pc. cable.Looks like the exsisting cable out the back of speedo exits thru the f/wall like a snake,not a straight shot from speedo to f/wall...couple of 90 degree turns.I am not comfortable in any of my cars while in cruise position,so no cruise in this 77. Will the column drop a little even though it is all hooked up from steering wheel to steering box. Thanks again,Mikey

No Cruise...what will you do with your foot on the gas pedal all the time.