If the head gasket blows between the cylinder walls, there might not be any water close to that area. I had a in line 6 in a 67 chevy van that had a blown head gasket between the cylinder walls and the PO had run it like that for who knows how long/far. It ran crappy and when you stepped on the loud pedal you could hear it popping through the carb. Upon teardown there was actual metal missing on the head and on the block. Believe it ot not, liquid steel worked for quite a while (as long as I drove it easy) before I dropped in a 327 SB. You do what you have to when you are young and do not have a lot of $$.