Oh I'm sure there is a caveat there somewhere. Ported vacuum has always worked for me but manifold vacuum is touted by many. Makes you wonder when and why it started.
Yea. There was another guy touting Manifold = Performance yesterday - I just replied.
But I do have a theory of where it came from. Just my opinion, but guys before Larry Shepard saw the long advance curves as a way to get easy starting on race cars - 1/4 mile Stock & Super Stock classes. This is what the Direct Connection tach drive distributors do. Then, perhaps not really understanding the implications, guys like Shepard setup the street/strip distributors with long mechanical advances. That's what Robb McC claims happened with the Mopar Performance distributors with the Mallory YH guts. So if one goes down that road with a hot rod, the base timing is insufficient. One way to bump it back up is use manifold vacuum on the vacuum advance.... sometimes it even works out. :):rolleyes: