1969 Mercruiser 165. Small water leak from under manifold.

[TheShadow619]

1969 Mercruiser 165 Inline 6. I have a small trickle of water from under the manifold between cylinders 1 and 2. I'm hoping that it's only the freeze plugs, but I know it could be the block or head. I know I need to pull the manifold off to check it out. My family has owned this boat since 1979. As far as I know the manifold has never been off. In looking at the length of the bolts I see a great possibility of breaking them off. Any advice before I dive in?

Other question is, can I use a standard manifold gasket from a 1696 Chevy 250, or is the marine setup special?

 

[TheShadow619]

No Title

Well... Good news and bad news.
The good news--- The bolts came out easily, the manifold came off easily.
The bad news--- The block is cracked. Had a lot of rust built up over it. Chipped it away, and the water started running. Got dark, so I will have to clean it better tomorrow, see what I have. I'm still optimistic that I may be able to use JB Weld to seal it back up. It worked on a cracked block on a 66 Chevy pickup I used to have, (Drove it for 5 more years before I sold it. Never leaked).
My Dad bought it back around 1979. My brother has had it for several years. I got it from him 2 years ago said he never winterized it properly. So it probably froze and cracked. It's important people, take the time to properly winterize your engine.