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What is max total timing for a 235? 30 degrees? more?

I have got one of these knock off MSD small cap HEI's. I am experimenting with the springs and limit bushings but would like point of reference. I generally time these by gauge and ear but would like to know really where I am at.

Thanks

Vacuum advance always adds more (if you have it).

I do have vacuum advance and we are using it. Right now I am set at 9 Degrees inital advanced. I have vacuum advance set at 20 Degrees all in about 3000 rpm. I initally had both light springs on the mechanical advance but then went with one light and one medium which brought it all in a bit later.

I will have to say this distributor and the dual Webers has made a marked difference in power.

Use a delay flash timing ight and plot an advance curve by checking the centrifugal advance every 200-300 RPM from idle until you get to maximum advance. In general, most engines perform best with 34-36 crankshaft degrees of centrifugal advance that comes in as linear as possible from just off idle and maxes out around 2800-3000 RPM. Add another 8-10 degrees of vacuum advance for cruise fuel economy. That will disappear as soon as some load goes on the engine and you'll be running centrifugal advance only during acceleration and anytime the manifold vacuum drops a noticeable amount. I've spent 40-something years tinkering with spark advance, either on a Sun distributor tester, a dyno, and/or a delay flash timing light.
Jerry