Need to Run [+]Lead Thru Firewall: '99 Grand Marquis

[LieutenantCracker]

Howdy!
I'm beginning the process of installing a two-outlet power inverter in my 1999 Grand Marquis, and I also want to re-route the poorly "rigged" POSITIVE-leads, that go to the flashlight charger & auxiliary cigar plug-bank (which the previous owner powered directly off of the factory installed cigar plug[!]). So, my plan is to run an 8 AWG POSITIVE lead from the battery, through the firewall and to a small distribuition block in the cab of the car, from-which I can then branch-off (individually in-line fused) POS leads, where I need them.

My problem is getting the wire through the firewall. The most common method I've seen is to bore a hole through the top of the larger of the rubber grommits, on the driver's side-- that comes out, under the dash, to the left of the brake pedal. But, I've only seen this on cars in junkyards; so I don't know exactly what method(s) is used, to make the hole. I'm just a bit apprehensive about "drilling" into this grommit, b/c of the fact that it already has an OEM bundle of wires running through the center of it.

Am I just being paranoid? Should I just (DISCONNECT THE BATTERY &) "be careful", and drill slowly..... or is there a better method?

Thanks!
________
350gtv

[way2old]

Go under the dash and look where the wires are coming through the grommet. Then use a sharp punch to make a hole. You can lubricate your cable and force it through the grommet. I believe there is alsop one on the passenger side that may not have as much in it. Good luck.