I have read that the ratio of hp to cubic inch ratio can determine when an engine will need an overhaul. For example:

CAT 3208 with 375 hp with 636 cu in overhaul would be about 5896 hours

DD 6-71 TA with 450 hp with 426 cu in overhaul would be about every 1056 hours

DD 6-71 N with 260 hp with 426 cu in overhaul would be about 6100 hours. A broker once told me that 6-71 N is the best engine ever made - they are bullet proof!

Any opinions on this method? I have read online that heat is the big enemy of any engine. The more hp the more heat produced, and the sooner major overhaul comes around.

I have also read that the cost of an overhaul can be around $3,000 per cylinder! If an overhaul is required every 1000 hours on a DD 6-71TA - I don't think I want DDs in my boat.

AM I WRONG IN MY ASSUMPTIONS?