Re: Block Leak
If its def coming from the block then its for sure a freeze crack. What you could try, and I've seen it work sometimes and other times it doesn't but it is worth a shot. Dry off the area, and marine tex the crack, let it set and dry, then sand it flat/flush. If it still leaks then atleast you tried. I've noticed it works best if you drain the blocks and manifolds, let it dry and bit you don't want the area to be wet. Get a heat gun down there if you have to and evaporated away any water. Mix your marine tex of choice color (i like black) and lightly coat over the crack about 1 inch around it. If the crack is deep and wide, like a gash don't stuff the marine tex in, just lightly fill it. Once its dry, sand it down and paint over it with mercruiser black engine paint.
When your done if the leak has stopped, congrats keep an eye on it and check it to see if its leaking again every once in a while.
If you do all this and it still leaks, oh well atleast you tried. Run it until it becomes serious. If your running in salt water hose it off with fresh water too keep corrosion from making the leak worse.