Just don't get carried away. I had a 67 Dart GT with the HP 273 and a prior owner had installed a 509 cam large tube headers and a double pumper. When I could get it to idle it sounded like a pro-stocker. It was the "getting it to idle" part that was the trick.
That one had been passed around some - the fellow I sold it to restored it and put it all back stock.
