Lets all get a true idea of what these original equipment heads are getting instead of all this guesswork. Mine are now 330 hours with absolutely no engine trouble.

If yours are rebuilt give the reason - just thought it was time, dropped valve, tulipped or burned valve, broken spring, etc.

Mine are at 380, getting done this winter. They are running fine, I'm just being proactive.

Mine were at 465hrs., just did them this past winter. They were still running great, leak down and compression was good. Rebuilt the top ends.

Interesting thread - if you have the breakdown of hours by RPM range from the ECM that would be good to know for a true comparison.

Slightly under 300 hrs when done as maintenance, have 330 hrs on them now no issues. We are second owner, first owner had over 100 hrs of idle time when we purchased with 260ish hours.

Had 2 CMI leaks, one at 200 hours and one at 225 hours. Heads had to be done both times. I now have Stainless Marine headers on there and there have been absolutely no problems.

312 hours and scared chitless ! Between the header stories and the valve train stories I am wondering why I had to have the 525's. Love how they run and sound tho , just nervous and don't want to pull engines this winter .

Excellent idea. Don't have my ECM breakdown at hand but I can definately say less than 3% at >5000 rpm, less than 10% at >4600 rpm.

Just passed 300 hrs here, less than 50 when I purchased the boat. Not a hint of an issue so far, I am looking to do at least springs and change out the Crane rockers in the spring, do a compression and leak down test first then decide from there.