Ziggy yes on 16% you can drop to .014 Change to a number 5 plug

Vaportrail: there not all the same but very very close. unfortunatly static compression means very little , or should I say it is only a good indicator of what will happen when the engine is operation at slower speeds and off the pipe. Lots of CR is good at low speed however detonation can occur as it comes on the pipe. The pipe and the boost it makes has more to do with what CR you want to run than not.

Generally on a 12 engine .004 thousanths will change the Compression ratio about 3/4 to 1 point. I said generally.

Somone asked about plug fatigue the other day, plug fatigue can occur under high sustained RPM's this is where the plug stays shiney and the wire just fractures for no reason. This is why I have always run Mccoy MC9 or the new Odonnell plugs as they dont do this. When this happens it is usually not a tuning or head clerance problem. If you see the wire start to pull out of the hole this means that the engine is scavenging really hard and when this occurs the engine is making serious power.