What are some general guidelines on recurving a distributor for better performance?

Question:

I drive a 1969 Chevy Nova almost every day and I have been making subtle performance modifications a little at a time. I am going to have the stock distributor recurved for added performance. Can you give me some general guidelines for what changes to make?

Answer:

The advance curve designed into your stock distributor is a compromise between performance, fuel economy, reliability and octane requirements. You can alter the curve (by changing springs and/or weights in the distributor) to increase performance without seriously diminishing the other desirable characteristics. Generally speaking, you should not alter the initial advance or the total advance from stock specifications. Change the curve so the total advance is realized sooner, but always avoid any modifications that cause engine ping or detonation.