Think about the horsepower it takes to move a 38' flat bottom boat thru the water. Light load doesn`t come to mind. I see your point if this was a car and you were just feathering the gas to keep it moving.

I have learned the more fuel you give it the longer they will last. My 600SC was pig rich (like most carbed Mercury motors)but that bastard would take a beating and keep on ticking. Fuel cools everything down in a endurance application. I see it on my intake temp gauge and EGTs.
The new blown Cadillac motor is programmed to drop into the 10`s after 10 seconds of WOT to cool the pistons.

I played the lets lean out the cruise game last year and while I had a bunch of other things going on I had to buy more that a few exhaust valves.
Give it fuel.. it`s cheap right now

I am not wanting to try lean. I am trying to learn and understand why these engines have lived. At the same time, I am trying to figure out how rich I really need to strive for. I understand I want to give it plenty of fuel on the top end - aiming for 11.5. Blown engines will need more fuel to stay cool.

Thanks for the reply!