I actually know the source of the blown head gasket... When I put the reman engine in, I put a brand new water pump in with it but that pump failed and caused an overheat. Not to the point that the engine shut down but I pulled it over when I noticed the temp was almost at the pin. The metal impeller actually broke off the shaft leaving a 1" disk on the shaft. I should have known something was wonky with the water pump when I had to shim the idler pulley to get it to line up with the belt.

 

i've had blown head gaskets without getting coolant in the oil, so one of these kits would definitely be a good idea. i also had never heard of them.