I just finish putting a new 502 crate engine (long block) in my boat and was wonder if there is a break in procedure? Or can I drive it like I stole it?

yes there is a 20 hr break in, below is out of the merc manual

GOODT......Thank you for that info. I really appreciate it!

A fairly high 2000-2200RPM at start up and held there for 15 minutes has always done well by me, even though yours is a roller cam that procedure is essential for flat tappet engines. I do it for peace of mind if something is going to go wrong I would much rather have it happen while I am right there and able to do an immediate shut down to prevent further damage that can be caused by putting it under load in the boat and not being able hearing things starting to happen. I run my stethoscope over ever inch listening for what ever check pressure, leaks etc., I know I have saved a few that would have gone south doing so!

Phil