@aslant My advice is to ignore the nonsense and/or ask them to take it to their own thread. Worst case start a new thread.
How do you determine what is useful and relevant and what is not?
Well one way is to learn
the fundamentals. That will help you seperate what is possible, what is plausible, and what is uh lets be nice and call it a misunderstanding. Whether to use manifold vacuum source or a ported vacuum source depends on the distributor design as well as the engine. When the spark should be fired at idle speed is effected by the timing of when the intake valve closes, the piston dwell time at the top, how much compression is generated at idle, how much heat is in the cylinder, etc. The fact is that Ford used venturi vacuum around 1949.
Chrysler used ported vacuum in 1959. Kaiser used manifold vacuum on their Jeep engines in 1963.
Chevy used ported vacuum on their high performance engines in in 1965. AMC used
a mix of both in the 1980s on their v-8s through a non-linear valve. What does this have to do with anything? Not much other than the following. Some people just refuse to let facts get in the way of their beliefs. The facts discredit the claims made that ported vacuum is a product of poor engineering, are an emissisions reduction method, blah blah blah. The facts can be independently and you should do so.
Another way to decide what is relevant is observe whether the person has any real first hand knowledge or experience, or is just repeating things he or she has been told and beleives. For me, once someone has been exposed as a BS artist, they are forever discredited as a reliable source of guidance. Sometimes these are well meaning people, but
as I wrote over at Speed-talk, they don't recognize the limitations of their knowledge. Knowing enough to be dangerous as we say. LOL. It doesn't matter if you were an engineer or a magazine writer.