Originally Posted by BenPerfected (Post 4498471)

We shut the port engine down and idled the last short distance to the dock. Per the engine builders request, we pulled the #3 & #6 plug and sent him a picture of each plug. His comment was they were perfect. Also we have zero soot on the transom. Much of the credit goes to the 1150 CFM Holley Marine Dominators. We quit bothering with the AFR meter as these carbs are spot on out of the box. We now also just touch the key to fire the engines and we can now idle at less that 500 RPM in gear. Docking is easy without stalling and not touching the throttles. Not bad for 500 ci 9.5 to motors making 780 HP. Only took us 20 yrs to find the right high HP combination that works in a pleasure boat.

Originally Posted by getrdunn (Post 4498480)

good job. I'm jealous. It would take most a lifetime or more including myself. I gotta ask though what rpm at 780 hp.

Originally Posted by BenPerfected (Post 4498409)

What do you think about the color of these plugs after a long hard run at 6000+ RPM....sorry about the triple attachment��

Originally Posted by Panther (Post 4499348)

Hard to tell from the pic. There should be a heat mark on the grounding strap which I cant see. Would need to see how far back the heat mark is from the tip.

Originally Posted by Panther (Post 4499350)

For me cruise RPM is anywhere between 3300-3800. 3300 is low 50's and 3800 is 62-64mph depending on fuel load.

I don't cruise at 4K+ because I start seeing boost right around there. 3800 is around zero and the boat is running a good number. Above that and into boost (1-3 psi), it starts sucking down fuel and for me it's not worth cruising at 4K+.