[Kenth]

I wouldn´t change the 2-bbl vacuum advance unless it´s broke or makes part throttle ping.
If ping occurs at part throttle acceleration you may reduce the amount of advance by shortening the slot, one quarter of the total distance, for approximately 15° advance.

If you need a new vacuum advance, Standard Motor Products got the VC24A (Dana B1) to replace both the 1116242 and the 1116243 controls.
Starts@8-11in/hg and gives max 16°@16-18in/hg.

Hope this helps some....