CR,
Welcome to the forum from a fellow 2005 460 Dancer owner. My wife and I are 3 seasons into our ownership and have had A LOT of work done on ours. The Cummins TSB that addresses the heads indicates that engines with an ESN earlier than 46634956 will have the old Exhaust Valve Seat material. So if your ESN is lower than this number and you do not see any indication that a previous owner has replaced the heads then there is a very high probability that you have the old style heads. The new Cylinder Head part number is 4942463.
All of that being said you should start with sharing your fuel burn numbers. I have shared mine extensively in previous posts so you can use the search feature and filter on my name and you will see all of the details. The long and short of it is that we have removed 2 inches of propeller pitch, replaced the RACOR fuel filters with SMX Double Double with squeeze bulb, added EGT gauges, replaced cylinder heads and the water pumps and added Wolverine Oil pan heaters. We had the work done in that order. Props were done 1 inch at a time in Jun 2021 and then before we launched in 2022. Injectors on Port engine were rebuilt in 2021, EGT was Spring 2022 and the rest was over the 22/23 winter layup including Injector rebuilds for the Strbd engine. In the 21/22 layup we had the electronics replaced.
We spent the 2023 season with all of the new stuff and the engines/boat ran nicely in all sorts of weather conditions on Lakes Erie, Huron and Michigan. We had this work done before parts and labor prices increased in a big way out here in Marblehead Ohio. Be prepared for a rather large bill for this work unless you are skilled in this work.
In the end the propeller mods have us burning fuel just a touch over the Diamond 450 curve in the 2200 – 2300 cruise range and our EGT values are what I consider to be in spec. The wolverines do a nice job of reducing but not getting rid of exhaust smoke at startup. We have 800+ hours on the clock, the turbos and exhaust elbows are in good shape. We are lucky to boat in cold fresh water. I almost forgot, we have had our entire cooling circuit serviced twice. Once when we first bought the boat so that we knew exactly what condition things were in and then when we had the heads done so that we could see what 2 seasons had done to the air side of the aftercoolers. Everything is in good shape. We have over improved this boat, no doubt about it. Let me know if you have any questions about what we did or why we did it.
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