'67 camaro max rear wheel size

[paco1112]

Does anybody know what the maximum size tires I can put in the rear of my '67 Camaro. I have 255s now but I would like the ability to hook up a little better. It is stock, not tubbed and I don't want any rubbing. If anybody has off set their rims to maximize the tire size without comprising the meat sticking out of the wheel wells please let me know.