I have a friend with a '69 Ford 429 engine in his Torino. It leaks coolant right from the iron on the side of the block.

We ran it on the lift at work to verify the leak...it only happens at operating temperature, pressurizing the cooling system has no effect on it. It leaks between the second and third expansion plug. There are NO cracks or holes.

I called the local Ford Guru, and he said "just take you a brass punch and a hammer there, and start at the middle of the wet spot and work your way around in a circle until it stops leaking".

I assume he means that the block is porous there, and that hitting it correctly with a blunt instrument will "rearrange" it enough to seal the metal.

???