My 64 Fury was upgraded to a 383 this past summer. Before I could finish the exhaust I ran out of warm weather. The dual exhaust that came with the car is just about new with Flow Masters, all nice and shiny. The car isn’t going to be raced and will just be used for cruising. Exhaust pipes measure just a little over 2” OD so I am guessing they are 2” ID. Question is, is it worth upgrading to 2 1/2” pipes for a cruiser from new 2” pipes off of HP manifolds.