Headbolt Thread Sealer

That will work well!

John, are you using bolts or studs? The reason I ask is on bolts you should be fine using that or ARP thread sealer. On studs, the threads are more rounded and I've seen more than a few leak with ARP sealer and/or Permatex Thread Sealer. ARP actually recommends - or used to when I did my engines a few years back- to use Blue RTV on the lower studs. Some old schoolers use Bar's stop leak on the bolts. Make sure you chase the bolt holes good and blow out with air. For head gaskets I like the Felpro 9333's.