Just curious about everyone else's usage/reliability/overhaul experience with these engines.

Hours of usage before a rebuild? When to rebuild? What components need at first overhaul?

Thanks!

Do you mean 575's?

Yep. My bad. 575s.

The blower is a weak link. Should be redone / upgraded by blower shop. About $1K per blower.
The 575 is well built and stout. I rebuilt mine @ 290 hours. When torn apart, all was fine and could likely have gone another 200 hrs. But builder said weak link was upper end. So have the valves and springs done if you have some hours.
Mine were upgraded to roller cam / roller rockers. Runs great and gets better fuel economy as well as a few more HP.
Best advice I can give you is to have the blowers looked at / rebuilt no matter what.

Jeff........just bought a boat myself with twin 575's.......did lot's of searching here on OSO. I found out some pretty good info and like Bill says the blowers seem to be the weak link. I took delievery just last week and already got myself a spare blower and will be swapping out one at a time to send for freshening up........just do a search for 575 and there is plenty to read........................................John

Smart, Johnny, very smart.

You are doing the swap?

Getting the blowers freshened up is a great idea at about 200 hrs and plan on doing the valve springs about every 250 hrs and an easy to pick up 80-90 hp is to put an intercooler under the blower while they are being overhauled. The bottom end of the engine will last for a long time I have lots of customers with 700+ hrs and still going just fine. By the way that looks like a great boat. Matt

Thanks Matt. Thanks to everyone for the info. I must have had a brain **** since I didn't bother to do a search. I'm sure there is a plethora of information on this topic. I will do the search now ... thanks to those who answered though!