NAPA had one size of braided ground cable the last time I asked. It was 6 gauge and inadequate for a 6v system.
Jim Carter indicates he has "correct" braided cable and that could mean 2 gauge or fatter. If it is 2 gauge, it would be OK, but a thicker cable would be better.
I use round/covered 2/0 (00) gauge ground cable and get it long enough to run from the battery to a starter bolt.
http://www.waltstractors.com/acatalog/Ground_Cable-Flat_Braided.html
