A-Body Autocross?
Well, I think it'll be costly to try and match the performance of any modern day mustang with a 40 year old duster. You would really need to do alot to make the duster competitive with modern day vehicles. What is your budget?
I expect AutoXcuda to chime in he knows what hes talking about and has a very sweet handling notchback cuda. All with Hotchkis equipment.