I am not sure just what you mean by Max advance curve. As for springs, I am a pack rat. I 've saved springs from so many distributors over the years that I can usually find whatever I need in my stash of parts. You can probably get springs from MSD or Mallory. Getting back to the curve, I've found that generally for every 1/16 in. that you shorten the advance slots you take out about 2*. So if you have a distributor with 13* stock [ pretty common ] and you shorten the slots by 3/32 in. you will now have 10* in the distributor. 10* in the distributor = 20* at the crank, so 12* initial will give 32* total mechanical advance which works well for a lot of mild performance small blocks. Big blocks usually like a bit more advance with stock heads.
