1968 Pontiac vacuum advance

[deanhickey]

I had my original Q-jet refurbished by you and am very happy with the results. My question is about my vacuum advance. It has to vacuum ports on high and one low. it is my understanding that the high on is the advance and the lower on is the retard. How does this work and how does it effect timing adjustment? Any info on this would be a help.
Thanks,
Dean
this link is to a video of the engine right after install.https:
     
     
https://www.youtube.com/watch?v=pQwDH2v-EBc

[Kenth]

https://firstgenfirebird.org/f-a-q/category/dtb/


https://firstgenfirebird.org/f-a-q/dealer-technical-bulletin-68-t-2-change-in-spark-retard-and-idle-speed-to-provide-smooth-engine-operation-1968-v-8-a-t/

[deanhickey]

Thanks for the links. they were very helpful.