Thanks Dan!

I decided to call Rod on this (havent had the chance to pick his brain on engines much). He tossed out 160-200 degrees as a rough rule, but said their are ALOT of factors that will determine optimum temps - % nitro, outside air temp, the plug your running etc. He did say I should start with McCoy 9's for my Novarossi's and if I want a hotter plug to try McCoy 59's or McCoy 8's. He said 1) it really comes down to reading your plugs; and 2) that "while most people can get their boat up on pipe and "x" temperature, but they aren't getting it hot enough to really take advantage of combustion and make power". The implication is that hotter is better (until you get to the point that the engine starts going through plugs).

He also mentioned that car/buggy engines have to much cooling for boats 'cause they're designed to run in an enclosed space (and in the hot sun) to ever get up to the temps that will make a boat really scream (and unless you do somthing to address this). Thought I'd share this info for everyone.