I just went to Charlotte two weeks ago and visited the factory. The guys there tell me that most people run a 34 Ford Coupe body and the 37 Chevy fenders/grill/hood. If you look at the 37 grill, it does not have the fiberglass "horse collar" around it so in theory the air flow is better. Note that if you change the grill you will need to also change the fenders and hood per the 2016 rule book. Not sure all of that change is worth the month compared to what those dollars would do with other things on the car. Hope this helps.