I have 10.8 to one squeeze in the 493 in the Charger. Edelbrock aluminum heads, MP '509 cam. Performer RPM intake, BG 850 carb and TTI headers. I'm also limited in my advance timing. In my case, its 30-31 degrees. I've been running Champion RC12YC plugs as per the Edelbrock instructions. I have a set of RC9YCs, but I have yet to swap them in. Several members here have suggested colder plugs for my detonation issues. Its been unseasonably cool here lately, so detonation has been limited. I'll swap them in soon though. THEN I'll know if they helped at all.
I've wondered for years: Do you make more power with LESS compression and more spark advance ..... OR more compression and LESS advance?
