Bruce ( Shrinker )

Glad it seemed to work for you but its not universal.
What is universal is the underlying physics of combustion, compression, and so forth.

manifold sourced vac adv. Others did not like the GM divisions
Just for the record.
1965 Cheverolet L-78 with 4150 list 3124
65l78_9_4cb76915662fccb81e408f6ad568bf5e10224fb9-jpg.jpg

This appears to be an original 4150 Holley List 2818
47682672d1319133625-numbers-for-an-original-holley-2818-choke-housing-2818rh3-jpg.jpg

As shown in this diagram
b-engine-ign-05-vacuum-advance-lines-gif.gif

Pontiacs until 1968 left showroom floors idling with 26*, 6* init + 20* MVA.
I don't have a Pontiac FSM. Would love to see that. Seriously.
I do see in the tune up specs that the v8s are to idle with 6* BTC at 500 and 600 rpm. That's pretty much what we'ld want for an idle rpm. Slip the clutch and if it has any torque to speak of away we go. :)

Kaiser's 230 Tornado used manifold vacuum port for its vac advance. What does that prove? On its own. Nothing.
Ford and VW used a venturi based advance system for several years. What does that prove? IDK. That they could skin the cat a different way. cool-gif.gif