Those with 500+ hrs on stock black motors. Have you replaced or going to replace valve springs as "regular" maintaince?

So answer the question. How is a 2 year old engine with 300hrs worse than a 10 year old engine with 300hrs?

More info:
The boat is immaculate. (I wouldn't be interested otherwise)

Its a 1999 Sunsation Aggressor. With a little 600 something hours on a 7.4 MPI.

I like the looks. But I think I could find a nicer one for about the same $$

If you like the boat and the price I wouldn't sweat it.
Just write an "offer to purchase" contract with a reasonable
(10-25% refundable) deposit and state that results from a survey on the boat plus powertrain and a seatrial are dealbreakers if they come back with results as to what you feel are such.
I, and a few others here, saw MAJOR price reduction below the contracted purchase price after the survey.
I got 25% of my price dropped due to non-disclosed baby pencilhead blisters below the freeboard for the price of repairs to sand them out and apply new gel coat.
I never saw my boat in person, only in pic's from the seller over 2000 miles away.
I had a TEAM MERC marina perform the powertrains first and the survey/seatrial afterwords
Most folks here will tell you that a survey by an accredited marine surveyor is your best money spent.
I'm sure you wouldn't purchase a home without a home inspection by a licensed inspector.
BTW, the only times my bud has pulled his valve covers were at each several hundred hours to look for sludge beneath.
The valvetrain is still stock.

See ya,
Kelly

I have 800 on 92 502 carb engines and they run perfect . I would say most of it is at 4000-5000 rpm! I have 2 friends with Formula cruisers that run pretty hard with well over 1000 and never opened up.

Think about this. 1000 hours on a stock 454 or 502 run at 30 mph for the lifetime is 30,000 miles.
ed

These miles are uphill pulling an overloaded trailer, in a boat. When you are cruising down the road at highway speeds your engine is turning around 2000 RPM's. I don't know too many people that cruise at less than 3000 in a boat. Also look at the MPG, that is a good indicator on engine load. A boat, depending on hull design, with a BBC will get 1-5 MPG. A truck with a BBC will get in the teens. Fuel consumption is related to load. 1000 hours is more like 200,000 plus miles.

I don't know when they started it but on later model Merc's the computer stores how many hours the engine has spent it each RPM range. I think it is broke down into every 500 RPM's. Ex. 1000-1500, 1500-2000...etc... I'm sure someone on here knows if your rig has this in memory.

That would be engines with a PCM 555 meaning 496 mag, 496 HO, 525 EFI......etc.

600hrs wouldn't scare me.friend of mine has a '98 38 PQ w/ T-502 with just over 1200 original hrs.Starting to burn some oil now but otherwise no issues