I actually answered this in your previous thread. These discussions get too sidetracked and its hard for anyone to stay focused.
And following up on that with Rick the more detailed explainations are here.
Too much timing?
I'll add this -
If you want to stick with the FBO plate, you may have trouble using vacuum advance. Limiting the advance can work, with the right springs in some engines.
If your not married to the FBO limiter and you have the original springs, then it may be easier and better to shorten the slots on the inside.
We won't know until we find out what the advance of your distributor actually looks like.
If you want to read some previous examples and explanations.
1970 Dodge Dart 318 Distirbutor
By shortening the slot on the inside like Rockable did
here, then its pretty much a pre-CAP advance. Everything will work as it should without changing springs. Small adjustments on the start can be done by adjusting the spring perches.
I think how and why is pretty well illustrated with Rockable
(360 Tune Up) and
further discussed with Mullinax."
Advance curves for performance engines using no vacuum advance (Race) versus when using vac advance.
Another timing curve question
Post showing adjustments to timing.
