Who told you that is not flying? That speed could embarrass a lot of performance boats :D

The chiller is a big deal for fighting detonation in the summer heat, along with that 120 stat. My guess is you are still on the cusp of detonation, and I am not sure the octane in the bottle is going to help you....never been a fan. A five gallon can full of race fuel to mix with what you have on the days you are going to run hard is a better choice IMO.

Keep that other pulley on the boat and don't be afraid to switch it out on the days you plan on holding it to the bar for sustained periods. Going up a jet size on the top end is not a bad idea either, too many variables in the marine world to rely on a plug reading you took today. Changing temps, baro pressure, humidity could bite you on a different day.

9:1 CR with 8 lbs of boost is pushing the limits of even 93 octane fuel.

Here is chart with CR's and boost # for reference. http://www.holley.com/data/TechServi...ech%20Info.pdf

Thanks Griff for the link, I was on that web site the other day. Didn't get all the way through. I see your point about the octane. Looks like I will keep it under 5700 rpm. Not sure if I will be able to even get there with the 27 but I'll find out this weekend. The game plan would be to get close to 80 with the 27p and leave the set up alone and be happy for the season. Ill keep you posted. I did keep the 3 1/4 pulley and belt on the boat.

There is always the option of putting on a methanol injection. Probably be my choice over octane boost. I would also ditch the thermostat. A motor will detonate just as fast if not faster in the cool fat fall air as it will in the dog days of summer. Good luck with your project I would take it easy until you get some kind of knock sensor meth injection or something of the sort on your motor it's definately living on the edge.

Add a wide band and meth!! LOVE THIS STUFF!! Man meth works so so well. Been running for years on boosted sled and now on my boat! How about 12-13PSI on 93 OCTANE at 32 degs!! Yea might want to try 29-30 for timing that is putting some heat in the exhaust side! She is possessed with this set up. But man watch that fuel you are running..... scary man... What temp plugs you running? 8 or 9s? Never forget i had a WRX STI all built and took to a new tuner. He added more boost and took timing out. Buy the time I got home after new tune. The turbo/exhaust side got so hot it melted my main wire harness!!! Not happy...... Car with old tune had 30,000 miles on it and never melted the wires.
Good luck be safe have fun!!!
P.S. Boost is so addicting be care full! LOL

Just an update. Ran the boat this weekend and it ran GREAT! Put 93 octane in and only ran it hard once Saturday for about 1 to 2 min to 7lbs max at 5400rpm.Topped out at 84mph with the 27p 3blade. Ran it Sunday for about 2 hrs cruising and the same today. Got home tonight and pulled the plugs and no splatter. Did a compression check ( warmed up the motor) and was between 145 and 150. Just for kicks scoped the #7 hole and it looked like cracks in the top of the piston? Spark plug showed no sign of any issues at all. I did put in some CRC octane boost previously with 89 octane (turned the plugs a weird orange color) and I wonder if its just my eyes playing tricks with a carbon/oil trail in the piston. Was going to spray some carb cleaner in the hole and see if it cleans up. Don't you think my plug would have been damaged also if I had small cracks in a piston. Seems to be running great. I have a knock sensor kit on order.

Yea u would see stuff on that plug. Plus you would see more than 5psi difference in compression. Sounds good keep 93 in her for sure!!! Screw that octane stuff....... meth man.... a real good kit is only like $500.00 so so cheap for what safety you are adding.

reconize the handle skydog on dootalk are you the same guy?

Quick up date. Brought up the #7 to tdc. Cleaned it off with long q-tips and got almost cleaned up. Cant reach everything. NUTS how nasty that octane boost crap is.
Has anyone ever put hair line cracks in a piston but not damaged a spark plug?

Yes