While this is a concours forum, what you're asking for is not concours. That said, you'll need to change your underdash harness, add the 3 gauge cluster and its harness, and to allow the ammeter to work, you'll need to change the headlight harness. The dash cluster will need to be changed to tach-configuration as well. RCCI offers a plug-in replacement 3 wire tach for the standard dash, using the standard dash cluster and its circuit card.
I can modify the underdash harness, build you the 3 gauge cluster harness but cannot modify the headlight harness. If you use the standard (non-tach) headlight harness, your ammeter will not have any signals. RCCI offers a voltmeter replacement. Right now, my services are down for likely the rest of the year due to repairs to the house/garage due to Hurricane Michael.
Hope this helps.