[buwalda]

Ralph,
Stick with it! If your adjustable vacuum adv unit has a notched metal plate to adjust total vacuum advance, it is probably the Crane unit. They are excellent, with good instructions. I have used many of them. They have a range of about 4" to 17" of vacuum, using the Allen wrench; I would try this first, as it is the easiest. Somehow, I think your problem is too much [total] vacuum advance, in which case you need to reduce it with the notched plate. If none of this helps, you could try retarding the cam 2 to 4 degrees. Whatever you do, keep the vacuum advance, as it helps idle, cooling, throttle response & mileage.
Good luck!