biggest tire for my Valliant

I ran 275 60 15s on my 65 for the street and 28 9 15 ET streets for racing. I used 15 x 9.5 Center Line Auto Drags I had the MP offset spring hangers. I did roll the outer lip, but only because when we went to the grocery store, it would scrub every now and then with my son in the back seat and a trunk full of groceries.