tires size?

[50bomb]

I have a 2001 silverado single cab shortbed v6. I bought the truck lowered which i believe is either a 4/6 or 5/7 drop. It has what I think are the original rims 16s. The tire size is 255/70/16 all around. They rub when I turn sharp. What is the period correct tire? I thought 235/75/16 was standard on the 99-02? Obviously I cant go with that cause its already about 1 to 1 1/2 inches from the front tires hitting the top of wheel well. Could I go smaller like 235/70/16 or should I just stay with what I have?