You should have at least 00 cables on a 6V. The battery ground should go to the bell housing. There should also be a ground strap between the bell housing and cab and another from cab to frame. It doesn't hurt to put another strap from bed to frame for good tail light grounding.

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.