There is a grommet directly in-line with the inside edge of the battery on the firewall on the passenger side. It's about 7" down and sort of lines up with middle height of the battery. I used this grommet this weekend to run my power wire to a new yellow top Optima. If you search this forum as I did you'll find numerous posts with a lot of photos that show the grommet location and routing of 1/0 power wire. The search engine on this forum is great and is truly your friend! I am almost done with a rather extensive install in and '05 SCAB with amp board and amps on the rear wall, big 3 (or 4), and dvd head unit. I have only asked the members directly for a couple of 'off the wall' suggestions, but the entire install including rear seat removal has been done using the search engine and photos posted by members.