225 or 235 drag radial enough tire?

Im in the market for drag radials for my 85 GT. By next spring the car will sit with 3.73s, full exhaust and slicks. I managed to get an amazing deal on some draglites for the slicks. They are 15x8 with 4.5 inch backspacing (yes i know, its bad backspacing). I was wondering if the MT 235/50/15 or a Hoosier 225/50/15 would be enough tire. I'm looking at these sizes so the tires dont stick out the fenders. I dont wanna spend all this money to wind up still spinning. I also am thinking about throwing on a 100 shot but I dont know yet. What do you guys think?
 
The BFG 275-50-15 Drag Radials will fit and work. I had them on my 82 with both 10 hole and Centerline Convo's and they fit and work fine. They are not too much tire! I would not go much smaller. This seems to be the most common size for the rear of a Fox. Mine is slightly lowered, and I did end up rolling the fender lip but only had slight rubbing on hard launches. They pull 1.90 sixty foots, with 4.10 gears on the motor.