We're working on a '66 GTO Convertible and we're going to relocate the battery in the trunk. I was recently told that I had to run a red and a black from the trunk to the engine compartment.

Because this is a full framed car, what would it hurt to ground the battery to the rear frame and then run a ground cable from the head to the frame?

I'm thinking that the reason for the second cable is because some cars like a Nova may have a rubber mounted subframe and an extra cable would be necessary. With a full frame care, I don't think that it would matter.

Any input?