Asking a flat head fan about their preference for dual exhaust compared to headers, is like asking for their preference in woman, when it comes right down to it, 'any port in a storm works just fine'.
When I first built the 59AB engine in my '36, it had a lot of modification of the day '53 done to it, the exhaust is stock '36 log manifolds with Douglas mufflers 1.5' pipes. In '54 I purchased a set of Belond headers, could not get them to clear the steering gears so I put the stock manifolds back on. In '55 I got tired of the noise so I put stock mufflers on the car... The quiet was golden...
In '75 I had a new exhaust system built for the car, stock chambered mufflers with 2" pipes, exhaust was a little deeper in sound and you could barely hear the cam overlap in the tail pipes on an idle...
I guess the difference with me is that I grew up a little, and I drove the car for daily transportation to and from work...