use an add a circuit and tap it into the fuse block next to the glove box. when I did it, I used a wire that had multiple strands, so when I added more gauges I already had power run to that area.
This.
Comp G. E85, 2.8, Headers, Tune, Intake, S1X, 105# springs, 60 # injectors, 255 walbro,etc.