Back to the drawing board... stock low dollar 360
At this point I've lost track of which engine this is for! LOL.
But if your curious how this plays out to a 318 with fairly stock cam and good low rpm combustion rates, touched on that here:
1970 Dodge Dart 318 Distributor
273 Hi Perf package is a good example of a timing curve for a burn that needs a bit more spark lead in the lower rpms.
In both cases, its better to have the long secondary curve into the rpms, especially with electronic ignition.
All of these are designed with vacuum advance in mind.
IMO the reason to use two different springs is to get an advance with changing resistance to rpm.
At this point I've lost track of which engine this is for! LOL.
But if your curious how this plays out to a 318 with fairly stock cam and good low rpm combustion rates, touched on that here:
1970 Dodge Dart 318 Distributor
273 Hi Perf package is a good example of a timing curve for a burn that needs a bit more spark lead in the lower rpms.
In both cases, its better to have the long secondary curve into the rpms, especially with electronic ignition.
All of these are designed with vacuum advance in mind.