Battery cabling/grounding question

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?

On all the racecars i have ever built that is the way I always done it. Ground engine to frame and also body to frame.

on my gto 66 i have the battery in the trunk i have the ground going to frame rail .i have the engine grounded to the frame .work s fine been this way for 15 years

Ground wire from the battery to the rear section of the frame, and the front section of the frame to the motor will be fine.
make sure you use 2 GA wire or bigger you'll be fine

i've done this on every car i've ever built and never had a starting problem. good batt , quality starter and a tuned engine is all it takes. i use 1 in ground straps from frame to engine and a couple of 1/4 in straps to the body. just don't mention this over there or you'll get flamed :eek: