I have a 306 with AFR 165 Heads, F303 cam and Edelbrock RPM intake, 24 lbs injectors. I have it at 13 degrees right now but I am having a heating issue. I had a 160 theromstat and I changed it to a 180 and still having the same problem. I think it is a timing problem. How much timing can I go up to and be save.