Advaced timing
 

I have a 1988 formula 223ls with a 454 330hp, how far can I advance the timing with out causing any serious damage. Someone told me you can gain 1 to 2 mph. Gotta beat me brotherinlaws profile.

You will pick up some power, but you will not be able to run wide open as long before detonation sets in. Sneak up on it 2 degrees at a time and don't go beyond the point the where the boat isn't gaining speed. Buy a spark plug viewer and make sure you are not picking up aluminum beads caused by detonation on your plug insulators next to the center electrode. If the boat is going faster, and your plugs look good you will have gotten closer to the edge. You'll probably end up between 36 and 38 for max HP. Good luck and don't be greedy, melted pistons could result.