Blas,
On my 1965 Comet I can take the gas cap off, it is a locking one and some kind of metal, then touch my ohmmeter lead to the edge of the filler tube and the other to the chassis and I do get a reading. It could be via the tank straps that hold the tank in but when I looked under it I saw a wire that went off to the side and to a bolt on the frame. Don't know if that was stock or if it was added as I bought the car used. When it warms up enough I will go check on the 69 Cobra and see if is is grounded. As I said in my earlier post, I tend to err on the side of safety. To many grounds won't hurt.One to few could possible hurt.
Ron
