Timing

20 I think would be just about bare minimum. You have a 18 degree stop inside your distributor? What is your cranking compression? How did you come to 38 being your sweet spot?...
So if my initial timing is say 20*, i have an 18* stop in my distributor. How do I keep it from total 38*? I know everybody is different, every engine isn't the same. Everything I have read is 34-36* total. I must be missing something (not understanding). I completely know how to set total on a locked out distributor. I haven't looked into it but can I buy a larger stop to lower total advance?