I have a 70 Ford Mustang with a windsor 302 and I was wanting to put some heads that will give me very noticable performance gains. Has Edelbrock RPM intake and has Edel 600cfm carb. Bored 0.060 over. MSD ignition. I was wondering what would be a good set for this everyday driver mustang. I have headers and heard the gt40p's are a pain with standard headers. !Dont know whether to go with cast iron or aluminum.! Any help will be greatly appreciated. (Edelbrock?, World Products?, SVO?, Stock porting?) Looking to do roller rockers at same time.