Hiding my 1/0 gauge in car.

[Tek18 10+ year member]

and you just drill up into the chassis to put it back in?

 

[ejschultz 10+ year member]

And use a grommet...

 

[maylar 10+ year member]

and you just drill up into the chassis to put it back in?

Yep. With a grommet. In my case there was already a hole through the cabin floor under the rear seat, which the factory had plugged with a plastic cap.