I would use the GM TEFLON bolt thread sealer and put the studs in. I've used this stuff several times now, and will use it on EVERY engine I build from now on that has a head bolt or even a bolt hole going into the coolant passage.
I've heard this is a great sealant as well.
I have a tube, ready to use, but chickened out as I'm plum tired of resealing them already.
I've used the Permatex white, leaked after awhile (runs on the track verses miles).
The ARP sealant is the current stuff I'm running. It holds on some of the studs, then starts to seep and leak on some of the others. I have a great pic on the Page of what this looks like on one that's leaking.. One good thing, if one of the exposed 4 starts leaking, even on a hot engine, you can pull it out with coolant bleeding and apply sealant, and throw it back in the hole and you're good for the rest of the race. Track frowns on leaks.
I've had two engines with studs, one of the engines still runs them, because it kinda has to. The other I had to swap to bolts and r&r the heads and gaskets because the coolant leak had compromised the gasket at one of the studs, leading to a small leak into the combustion chamber.
If we could get the same sealant that's used on the head bolts applied to the head studs, we migth have a usable fastener.
Otherwise, RTV them in.
Looks like my comments about leaking studs got your attention Bobbie.
J