That depends on your total breakin hours that you need to achieve ? Id leave in and finish the breakin in the spring, I mean there's no reason to throw out good oil. JMO

I was thinking the same thing but just wanted someone's else opinion. I wanted to get at least 12 hours on it. Boat will be sitting for 7 months before we run it again.

If it's been started up, ran up to temp a few times and run at RPM I'd personally consider it broken in. With todays ring and hone technology 1 pull on the dyno at temp it's broken in. If a bearing or cam was going to go it's going to go...
IMO Get it out of there.

I’d agree 100%. After half dozen runs with tcool downs in between call it good.

Makes me wonder how all my engines survived so well back in the day with just good quality oil for break in. Then again I was never the greatest with break in anyway!

something similar to this ? what boat is it in.....Chris Craft , Hacker, or Century.........Id break it in the way the machine shop recommends

That would throw my ol man’s theory right oh the window. He raced just about everything imaginable and said break em in how you wanna run em! Yeah old school but somehow he managed. Lol 😂

Years back when I built some 540's with Brad Smith, we hooked the first one on the dyno and I said we gonna break em in he said sure, started it up loaded the brake ran it to 4k then back down to idle, then pined it to to 5600........he looked at me and its broke in.....lol

Perfect 👍