Leaking Freeze plug or cracked head?

[LCYrace]

Out today to test my fin realignment and noticed these rust stains. Obviously the freeze plug is leaking when the engine is hot. Should I replace this plug or just let it ride. From the looks of it, it has been like this for a very long time. There are rusty streaks all down the side of the motor where is has been leaking. So how would I determine if the head is cracked? The motor pushes the boat to 40-41 mph at 3900-4000 rpm. I think it my be a little over propped. Could it run this good with a cracked head? Anyhow I need a little direction. Thanks again!!!
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[Jetlink]

With a 1:1 transmission like most of our boats, when propped correctly the tachometer should read close to the MPH. So, if you're getting 40MPH while turning 4,000RPM I would be inclined to say your spot on from a prop stand point.

[DAFF]

Use a fine brass wire wheel and give the area a quick clean up. From the angles I have a feeling there is a fine line crack. Take a picture from the exact same place from the other side of the engine for comparison. As for the running aspect if the crack is not in the compression side of things or into a oil passage then you might get away lucky. If it does turn out to be a crack and it is fine I have an idea to fix it without removing or replacing the head.

My idea involves Iron Tight and I have seen some amazing results from this product. Only issue is its normaly used on a closed looped circuit. I think if you got the engine hot on the trailer. Removed the Tstat and plunked the solution inside the block, restarted the engine with the Tstat back in place it might work. That is if there is a crack in the first place. As for the frost plug, remove it with a screwdriver and replace. They are very cheap.

[villain]

I would remove and replace the plug. They are cheep and easy to do. It would be strange for a ford to crack right next to a freeze plug and not push it out even a little bit. When you put in the new one, put some locktite on it to help seal it in place. Make sure to clean and inspect the area really good when you have it out.

[LCYrace]

I can't believe I bought a boat with a cracked head............

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[villain]

that is crazy, i have never seen a ford head crack in that location. if you swing by a machine shop they should be able to braze it back up for you in a matter of minutes.