like the title says....i need to fit a 0 gauge through my firewall and when i poked my head down there i couldnt really find a great place to poke through but i didnt move much around to look.

 

there is a rubber piece that goes around the main wire harness on the drivers side firewall behind the fuse box. there is plenty of room to go between the wires in the middle and the outside of the hole. cut a hole in the side of the rubber and use a screwdriver to push out a second piece of rubber inside the rubber piece. you should be able to pull this piece down the harness a ways from the inside and have no problem fitting 0 gauge in there, at least i didnt on my truck.

 

The harness that 53bowtie referred to is what I have used to run multiple wires through the firewall. Nothing as big as 0 guage, but enough wires that probably equal up to about half of that. I undid the elec tape at the ends of the grommet and carefully/tediously snuck wires through one at a time as I added things on. I think the best bet for you would be to make holes on both sides of the grommet to slide the wire through. If you have some form of pipe that the wire will fit into, you can grind one end to a sharp point to pierce the grommet, then run the wire through the pipe, and finally remove the pipe. If you don't have any way to do that method, a little silicone sprayed on the grommet and wire helps it slide through easier...as long as you don't grab some of the wire that you lubed and end up with slippery fingers.

 

Here's a pic of the grommet that we're talking about...you can see some of the extra wires that I ran through mine. You'll notice that there's a pretty good amount of rubber (or sidewall lol) that you could pierce and go through. Another alternative, although not my favorite, is to drill a new hole and install your own grommet...personally I don't like to make extra holes if I don't need to and I try to keep things looking somewhat factory.

 

wheres the pic? i will check this grommet out in the morning...hopefully ill find it but if you have that pic handy and can post it no problem i would appreciate it

 

I only had to run 4-Guage and squeezed it through the same grommet as the Drive-by-wire goes through(just to the left of the bulkhead, closer to the Brake Booster). I used the trusty metal coathanger and duct tape method for poking it through the grommet There was also a handy channel in the rubber mat under the carpet that ran from right under the grommet to the rocker panel where I finished running the wire to the back.

 

got it through, thanks all

 

Whoops...don't know how I forgot to link to the pic, sorry about that Sounds like you got it worked out anyway. A little late, but here's the pic (if it works this time lol):

 

ha no problem. i actually feel kinda bad for posting this...probably should have just not been so lazy and looked for more than a split second