Washington,MO ?
Hey, this must be Zane......Right? I know I have seen that car somewhere before.
I replaced just my cable insert from the dashbaord end of the casing and it wasn't too bad
Get the band-aids ready! your knuckles will be hurting.
One tip, remove the drivers seat ( only 4 bolts ) This gives you much more room to work in while laying on your back with your head up over the clutch pedal :L
This really does make it easier!
On the back of the speedometer is a metal clip like thing that you depress and it lets you pull out the cable casing end, you can see it if you stick your head way up there. Then fish it through the firewall and un-screw it from the transmission. (sounds easy anyway).
The cable casing is very stiff and hard to work with, have patience, make sure the cable itsehlf is inserted "Squarely" into the trans and then the other end just snaps back in to the back of the speedometer.
I do not know what the directions say, but, I recommend secureing the transmission end first, and the back of the speedometer last!
Good luck,
Maybe I'll see you at Chevy's May 6th
Tom, Route 66 Corvette Club, St. Charles County,MO.