i just got my cam and heads ( ported stock heads and gmpp 847), and know ill be needing more timing down low.should i tweek the spark at 100 and 90 kpa map in the main spark table? i have a tune already, and im not sure if this is done yet.also,how many deg should i try for, i know to monitor with datamaster so i can check for knock, but i would to be able to get it a close before driving.