I am purchasing a well maintained boat with twin carb 500Hp's. There are 335
hours on them. Typically, when do you have to look at springs and or valves with these engines?

Thanks. Dan

Dan,
When I had my Formula 382, I put 450 hrs on them before I went through them. They were fine other than a little corosion on the exhaust valve stems on the rear two cylinders on each engine. If the boat has been well maintained and you know that personally, I would think if you took care of the engines and weren't out running the snot out of them every weekend, you should get 500 to 600 hrs out of them.
Robert

I Agree With Tonto But I Do Think That The Heads Should Be Gone Through After About 185 To 225 Hrs Because The Only Failures I Have Ever Seen Out Of These Engines Has Been Valvetrain Related . Good Luck Laz Mesa

Thank you for the feed back. I spoke with Pro Marine who although is not the seler did all of the service. It appears to have been very wel mainteined.
I am picking it up Friday...

Take Care. Dan