Father-Son 1974 Duster Project
That's cool. This 40 amp switch in a black box tucked in under the battery tray will be fine. A switch like this is rated for contact at 40 amps. Since it will only break the circuit when the car is not running the switch will never be exposed to stress. I could run 70 to 80 amps through that switch once it's in the on position forever and never have an issue....