What battery are you using in your trunk also push pull turn off.
Obviously an Optima red top with top and side lugs.
I didn't want to drill any new holes for the switch lever in my nice, original tail panel or tail light lens so I ran it through a space between the license plate and the bumper. Not sure if you can do it that way on a 'Cuda. The part of rod that sticks out past the bumper got trimmed after this picture. Moroso 4 lug switch with the bracket welded to the trunk floor. The trunk was painted afterwards.
The long, bent rod probably looks a bit clunky but it works perfect. No longer using the box since I have several extra battery connections. The box is supposed to be sealed which is out the window with the holes. I had to fab up a rear firewall panel because of that.
On/Off lever.
Rear firewall. Got the .032" aluminum sheets at the Bargain Barn in Meriden.