I just addeda factory tach to my 67. I had to remove my oil pressure and alternator gauges to put the tach in. Because myinstrument wiringharness isn't the same as the "with tach" wiring harness I can't make use of the oil and alternator lights on the tach. I currently have the oil and alternator gauges connected and just hanging until I mount them somewhere else.

Can I disconnect the two gauges for now until I properly mount them (or new ones) somewhere else or do I have to have them connected? My buddy claims that the gauges have to be connected in order for the car to run well. I dont know why, so i'm asking here.

 

The Oil gauge can be safely disconnected, but I don't know about the ammeter. Maybe someone else can help.

If you disconnect anything make sure you protect the wires from shorting to anything else (I.E. tape them up)

 

There is no problem disconnecting either gaugeand neither affect how the car runs. In my review of the factory tach installations these circuits aren't affected so why you want to disconnect them is beyond me. Be sure to tape the ends of the wires if there is exposed contact area (or just to keep them in place)