I think you are going to have lots of problems getting that installed. No
tach, to a  cluster with tach, wiring. The dynamic oil pressure switch may
be an issue. Never needed to do this change over, and I am sure it can be
done, but I dont know how to do it.

If it is the tabs that attach the cluster to the dash, just position the
cluster as you want it to be. Drill a hole through the plastic of the
cluster, and into the steel of the dash.Do this in an area between the two
tabs on each side. Use a screw to secure the cluster to the dash. It wont
ever budge.

If the cluster has broken corners where the speedo meets the clusters'
rear, use longer screws to reach the remaining threads. Seal the broken
corners so dust wont get in to the speedometer. Use silicone in a tube to
do this.Best to clean up all the components of dust, first.

Put the dssh cover back over, and you wont notice any difference.