Easy Question? 67 F-body Rear Tire Size/Rim Backspacing

[mitch_04]

My dad wants to jump (slightly) out of the past with his big tires sticking out past the fenders on his '67 Firebird. It's the way his was in high school, so that's how he built it. Now after seeing a lot of cars with "tucked" rims, he has decided to slim down a bit. He still wants to keep the 15" Cragar SS rims though...



My question is

1. What's the widest tire that fits in a '67 Firebird rear wheel well with no modifications?
2. What offset does the rim need to be at for the tire to fit?

I wish I could talk him into even 17's, but it's his toy and his money. It still draws a lot of attention, and most of the people around here like the wide tires sticking out past the fender and the back end jacked up look. I guess it's a generation thing!