Forum member,
Most head gaskets fail due to the following: 1. Unclean surfaces
2. Block and or head surfaces not perfectly flat. Have surfaces machined.
3. Stretched head bolts. Should replace with new.
4. Bolts bottoming out after machineing to block and heads.
5. Incorrect torque tightening.
I install head gaskets dry and use ACL brand gaskets up to about 170HP and Cometec brand from 170HP to 220HP and then custom made (with a fire ring).
This may assist.
Regards
John