Mini tubed you should be able to get some wide ones on there. Go with a 17X10.5 wheel with a 315-35-17.
Lidio is a great tuner in this area, he has an 88 Notch with some huge rubber under the back....I believe 345-35-18's The wheels are about 11.5" wide. NO tub, but some massaging of the rear frame rails, and no tail pipes. I drove behind him this year on the Woodward Dream Cruise, and it was SICK!!!!