I've had the D-451 and 452 headers on my 440 powered 65 Belvedere.In both cases #6 plug is a real PITA to service due to access. Anyone devise a solution to that problem?Also, I'll add that the end of the Pitman arm and the steering arm just touch the header. Other than nicking the coating it's no issue even when turning the car.Akron DonDon Gallimore