Tire rub issue

[CR67rep]

Greetings all. I miraculously got my CR thrown together in time for Hotrod Power Tour and completed nearly 2500 miles of driving in 9 days. What a trip! I did some light Autocross action while on the tour and found that I've got some tire rub issues when turning hard. I'm running 15'' Cragar wheels with 255/60/15 on all 4 corners. This was the set up when I got the car. I've not had a chance to pull the wheels and measure back spacing yet but was wondering if the 255 is maybe just a little wider than what most run on the front? Or is tire rub just something these cars are known to do? I did a search and found that a lot of people seem to run 245 in the front and 275 out back. Thanks in advance for any insight! Also as far as suspension goes I'm still running the stock MII springs and a-arms. I did replace the shocks right before the tour though. Maybe the spring rate is too soft? It's a 350/T5 car.