Exactly. I said it was BIG Myth. Case in point.
It's an easy conclusion to come to when just experimenting with switching to the the manifold source using a distributor designed for a retarded initial timing - as many of us have. Its actually a better method than just advancing the initial - which leads to all sorts of problems because of the timing curves.
That's why I invited everyone to go look at the original material themselves.
When using a distributor that doesn't have a curve to compensate for retarded initial, then ported works out better - and especially with a hot cam - its more stable.