How to limit total advance on a stock SBF distributor?
Here are three options that may work for you.
1. Look through the junkyard for a plate with lower numbers i.e. 13L (26 degrees) or 10L (20 degrees).
2. Another item to look for would be a small plastic clip the snaps on to the tab in the timing slot. I found one in a truck; it limited the total a few degrees.
3. Tack weld or solder a portion of the slot closed, then file away until you get the desired timing total.
Hope this helps. What distributor are you using?
1963 Falcon Scat back 302, C4, 8inch 3.25 open.