Change out all of the one gauges for aftermarket??

I'm in process of rewiring my 68 barracuda,
I would like to reuse the original gauge set (as well as add a performance gauges). It is a pet peeve of mine to have inoperable gauges in the dash.

Has anyone done this with an aftermarket harness???

I am using an American autowire universal harness.

Looking for a little help on how to do this.