Ok What's your guess??
 

Ok here is a small video (no sound) of my 454/400 cyclone that I just got started today for the first time since I got the boat. She sounds great, no knocking etc. but my starboard exhaust is burning some serious oil. I'm guessing rings but any other thoughts? I'll know for sure in the next week or two once I pull the head.

I would think rings also, but it could also be oil bad oil if it has been sitting for a long time...and it is oil burning.

I can't tell if that is blue smoke or white on the video.

...it looks white and that would be water as is a head gasket.

I would run a compression test first.

ide pull the plugs and see whats on them. is it possible that the cylinders were filled w/ oil when it was stored and thats what you are seeing being burned off ?