For those of you running 496 425HP engines how many hours can you expect to get on well cared for engines that are not run hard? (twins in Fountain 35')
Are there any items that require special care?

1000+ shouldn't be an issue. I've heard some say 2000.

Idle Air Control (IAC) valves are a common item to fail on these engines. When they do fail, they can damage the ECU. So, many change them every so often and/or carry a spare. Much debate on if the aftermarket units are good or not to run, so I went with OEM.

1,000+ in a performance boat. I've heard of 2,000 in cruisers as they aren't typically run as hard.

I hope 1000-2000 hours had my boat a few years 400+ hours not in love with 496 HO but changing props next season we'll see? Turn back time 525 FWC motors?

Shying away from 525 engines due to running in salt water. Not sure how long those expensive headers would last in a salt environment even with religious flushing...

??????? 525 SC or 525 EFI ? There are thousands out there with no issues. Why would you worry about the headers and not be worried about the manifolds?

Here are the bearings out of my '04 496HO at 400hrs. They looked new. The cylinder walls had perfect cross hatch still. Engine could have gone well over 1000hrs I think.