I replaced my original 8V-71na engines with 6V-92TA about 30 years ago on Jack Hargrave's advice. Picked up 200 hp per side at 550 hp. Mine have been virtually flawless. They don't leak oil and I went with the mechanical version instead of the then brand new DDEC option which, in hindsight, turned out to be wise. Other than one ten minute full throttle burst per season I never run above 2000 rpm. Changes in instrumentation make it difficult to come up with exact hours but I estimate about 3,500 hours. I contemplate the present "good" original O-rings on the cylinders with a possible rebuild with new, but perhaps questionable modern rubber O-rings. I currently lean to the "if it ain't broke" philosophy. Guess I will see. Excellent engines in my experience.