I asked in a FB mopar group a while back VA ported or not. The whole thing got pissy fast. I was surprised how many people don't, won't try to run manifold vacuum. 68 was the year Mopar changed over, 65 in Cali I think for emissions.
You can often use manifold vacuum to offset the the retarded initial timing on CAP/CAS set up. Its a lot simpler for many people than correcting the advance curve.
However, since this thread is about myths, its a myth that ported vacuum has anything to do with emissions. This is a big myth, and I beleived it toountil a couple of old time tuners set me straight.
Then I started looking at stuff written and built at the time - particularly Chrysler stuff.
Go look through shop manuals, the MTSC, at photos and surviving example and it will be interesting to find what year or years Chrysler first used a vac source above the closed idle position.