Rats, posted it all then lost it. First, you should not have to remove the airbag. You can slide the whole cluster out behind it. Here's the drill:
Remove headlight switch knob and dimmer knob
Remove lamp switch cover plate, disconnect fog lamp switch if installed
Remove two guage panels to right of cluster
Remove four cluster screws
Pull the cluster forward, further out on the right side
Hand behind the cluster, disconnect the two big multi-plugs first
Disconnect OD lamp wire in right corner
Disconnect speedo plug--watch for white retainer bracket over plug, careful!
Note and disconnect other wires, but I think that's it
Slide the cluster out over the column cover to the right
Unscrew and remove clock, replace with tach (nuttin to it)
Locate the tach lead in the bundle behind the cluster. White/red, female spade
Replace the cluster. Leave it further out on the right and connect all but tach
Tilt it in on the right, connect the tach lead to the tach. Lower two terminals at the bottom are the ones, doesn't matter which.
Bolt it all back together and you are done.

Enjoy!!!

DS