Try some of this stuff
http://www.permatex.com/products/aut...ve_Sealant.htm next time you install head gaskets. I built a few engines in the past(v8s and motorcycle engines) with this and it works well. It works so well I ran my 79 YZ400 without 1 of the headbolts for a while
and had no problems, except when it came time to replace the piston almost didnt get the head off
Some racers around here live by it.