Drill hole through firewall

[tmontague]

There is a large 1-2" diameter black rubber cover right behind the battery. The large wiring harness goes through it into the cabin. You can barely see if but you can pierce it with a coat hanger and when the coatr hanger it half way through tape your wires to it and pull the coat hanger from the cabin. The hanger will come in above the clutch pedal.

I did this for my gauges and it was fine. The pita is to find it and get the coat hanger through it when you've never done it before. I'd avoid drilling if possible