spot for amp power wire

What's up all? I've looked through quite a bit here, and also tried the search function with no luck in finding a solution to my problem. Fortunately enough it's not anything extremely drastic or world changing. 

What I'm working with is an '07 Tahoe. What I'm trying to find out is if there's an existing spot on the firewall where I can run a power wire through for my amp. I spent a fair amount of time earlier looking both under the hood and inside under the dash, but wasn't able to see anything. I know one solution would be to drill and make a hole of my own, but would really rather not have to go that route. Wondering if anybody knows of a spot that I didn't see? Thanks in advance.

Brian

Is there not a large bundle of wires going through a large rubber grommet in the area just forward of the brake pedal?

There is a large grommet behind the parking brake, but getting a large cable through it may be difficult and it won't seal to well. I would suggest drilling your own hole and use a grommet to pass it through the firewall. If you unplug and remove the large electrical junction block on the firewall, next to the parking brake, you should find a flat area on the firewall that will allow you to drill a proper hole.sparky