[flipper35]

For total advance the plug position, piston shape, combustion chamber shape, cam and more will determine what the total advance should be. My builder told me that my flat tops should be at 34, but if I went with a dome style it should be 36 even though the CR would be higher. Something to do with the flame front. Mr. Fixit could probably splain much better since I is only repeatin' what I heard.