This bike is not a 600...but they had no proper name listed as an option. This bike is a 62' Atlas with extensive mods. 810cc Dunstall cyl. 4s Dunstall cam, Combat 32mm head dunstall porting, lightend and polished. 32mm amal carbs, lightened and balanced crank, matched rods, magneto ignition...Quite the beast. I snapped two trans cases. But it handled like a dream.