Had a head gasket on my IH C leak. I replaced it. However, where it leaked really wasn't a problem. The antifreeze seaped down the side of the engine. No antifreeze got in the oil. No biggie. I will add stop leak the next time it happens. Will run without a pressured rad cap until the stop leak works.
Where mine leaked, the antifreeze was less than 1/4 inch from the outside of the block. I think the gasket may have gotten damaged by using a pressure on the engine. My lesson learned, is I will never use a pressure washer on a tractor again.