Amplifier Wiring 4ga Pass-Through to Cab

[82TwoHeadlight]

I'm interested in how other board members are passing 4 gauge audio amplifier wiring through the cab. My amplifier requires a 4 gauge wire attached directly to the positive terminal of the battery and I don't want to drill another hole in the firewall if it isn't necessary. Pictures and descriptions of your methods are greatly appreciated.
How would you recommend passing the wire through to the cab?

 

[PrairieDrifter]

There are only a couple holes by the brake booster. If an a/c truck it should have one by the engine bay hvac box for wiring and one for the vac tube, 80's at least

 

[WFO]

My amps are under the seat. I pulled one of the floor drain plugs and replaced it with a grommet. Ran the wires along the frame then up through the grommet, then put silicone in the grommet around the wires.

 

[Grit dog]

There’s a large hole coming up from under each cab corner to behind the rear corner speakers.
That’s where I’m going to pull power in from under the hood.
You could run 2/0 through there if you wanted. And no drilling. (I think. Been a while since I hatched that plan).

 

[82TwoHeadlight]

Thanks @Grit dog
This is the method I chose. It was easy to route the 2ga and the wire is mostly hidden. I was able to route the wire inside the passenger front fender down under the rocker panel and then up through the cab corner using the factory rinse plug in the cab corner.
I made a mount for my amp out of aluminum strap and ABS plastic. I formed the aluminum to use the passenger rear seat bolt as a mounting point and on the amp side I screwed the strap to some ABS plastic that serves as an insulating mounting tray for the amp. The inboard side uses another piece of abs at a 90 degree to the tray to suspend the height so the amp sits level. Wires are run under the floor mat:

 

[Grit dog]

@82TwoHeadlight, nice clean install!

 

[SquareRoot]

I used a bulkhead connector on the firewall. Comes thru behind the p/s inner fender, below the a/c box on the inside.