Engine Hour totals

[rdtahoe]

I read somewhere that in marine engines, 3000 total hours of running was about when the engine should be near rebuild time.

Was wondering if there were any comparable numbers for auto gas engines. I read that 5000 hours running time was fairly typical, but that may have been "back in the day", before the use of synthetic oils.

Any of you guys have any ideas on this?

Thanks...