A tip on installing head gaskets. Here's what I do re-installing a head after pulling the head, pressure testing it , and resurfacing it:
1. Gently scrape the block and head surfaces, then clean the surfaces with lacquer thinner and clean paper towels.
2. Keep cleaning both surfaces until you can wipe the surfaces with a lacquer thinner soaked clean paper towel and the towel STAYS CLEAN.
3. Coat the block and head surfaces with about three(3) coats of aluminum paint, i.e. the type aluminum paint that is sold for use on metal stove chimnies.
4. Also coat the gasket with aluminum paint as well.
5. Bolt the head/gasket on by incrementally increasing the torque. If a straight six, one of the front head bolts is at a lower torque than the rest of the head bolts. Check your manual to ID that head bolt.
6. Fire the engine up and warm-up to operating temperature and shut down.
7. Retorque the head, run it a week and retorque it again and maybe one more time. Keep re-torquing the head until the torque does not change after cool downs.The re-torquing is REQUIRED because the head gasket/aluminum paint is compressing down and the torque is being reduced. Likewise, the head bolts are resettling because of sealant softening on the bolt threads.
This is an "olde hot rodder's/racing trick" that works. Years ago many gaskets were aluminum paint coated. The aluminum paint fills/seals the metal surface pores but also allows the head to expand and contract WITHOUT tearing the gasket. Coating a gasket with teflon and assuming it will expand and contract without the teflon "digging in" and tearing is wishful thinking. Thermal expansions, in heads, are typically large expansions and large expansions/contractions can tear gaskets or teflon coatings. In my view, those gaskets sold to be torqued once and forgotten about -are a joke. Hope this helps!
Best regards,
CJR