Well, I do have and exhaust leak (at the header). When I got the engine, the top right (looking at the engine) manifold bolt was busted off. I just haven't got around to doing anything about it.
I was running 94 octane for awhile but noticed that nasty soot all over my car and realized I wasn't burning it all (obviously). I decided to stop wasting my money and switched to 89.
What should I look for, to know if I am detonating? (without tearing apart the engine)