I was thinking of going this route, for a 97 zr 440 set up for sprint oval racing, I have the stock 6 3/8" rear idlers, was wondering if instead of going that route, to go with say 7 or 7.5" wheels. could I just replace the original idlers with these with no other changes? reason for this, is they say you can get a few more mph, any truth to this.