[Gromit]

Not sure how much I can quote Mr. Ray and stay within fair use but here are a few of his good thoughts on this topic and hopefully this is enough to help:

"Notice that the OEM GM advance has an addition to the pull pin that passes through the advance mounting bracket, a section of rubber hose is covering the pin, through the mounting plate. This rubber tube (stop bushing) is there to both cushion the advance at full degrees stop, and LIMITS STOP degrees down to the correct specification for that advance/engine application.
These rubber stops usually degrade over the years an engine goes through running the bushing against the stop slot, and engine heat cycles, chemicals that get under the distributor cap, and can disintegrate, and/or fall off the pull pin, eliminating correct degree stop.
The after-market advance shown does not have any stop on the pin, as they are NOT supplied with the advance, and, when used thus, gives far, far too many degrees of vacuum advance for the application."


All I can say is I've researched this enough to satisfy myself anyway - not trying to convince anyone here. I agree with you about starting world war three on manifold verses ported.. LOL I just liked the way Dave Ray thinks on this topic and his advice has worked for me.