It does take a bit to get it to move...the way to check is to hook up a timing light with the vacuum advance DISCONNECTED and start the truck. Check the timing and see where it is...dont need to be real exact here just for a check...then with the light still on, hook up the advance and the timing should move noticeably...if so, it works.
If you go through and figure exactly what the timing is in connected and disconnected modes, you can see how many degrees difference you are getting...I am not sure what the degree difference is offhand...maybe someone else has that info...
Lord send your Holy Ghost into our hearts and make the desire of our hearts Your Will.
Pro-choice, that's a LIE, babies don't choose to die!!