Rocketman makes the mini tachs & converts the clocks to a quartz movement which is much more reliable.
Instr cluster removal, PITA level#2:
Remove steering wheel and T/S switch arm.
Remove Heater & A/C Control panel
Remove dash ashtray & mounting bracket.
Reaching in through Htr/AC access, disconnect 2 cluster connectors, connector to W/S wiper switch, and speedo cable.
Reach through the ashtray access- there is a nut that secures the Instr panel & center dash panel to the dash. Remove the nut. (5/16" wrench IIRC)
Remove 5 Philips screws from Instr cluster (2 @ bottom, 3@ top)
Remove Instr Cluster, pulling straight back, maybe wiggling a bit. Don't scratch paint on column.
While the cluster is removed, do yourself a BIG favor:
Clean the instrument faces.
Replace instrument lenses.
Paint instrument pointers (Dayglo orange/red)
Replace ALL the bulbs with LED bulbs (I even remove the blue filter caps).
Replace the 6 volt instrument voltage regulator with a solid state unit.
Hope this helps.
Neil