exhaust coolant bolts

[charger72]

i recently had the heads and cam redone on my 318 in my truck, but the right rear coolant passage bolt for the exhause keeps leaking past the exhaust cap bolt i used even with silicone. How can i fix this?
I prefer cap bolts as they can come off alot eaiser later.
also, i do have cap bolts on the others and they dont leak. should i use a longer bolt? the original studs were bad so i took them out.

[RallyeMike]

Use the telfon seleant meant for sealing water passages and plenty of it. Dry the hole before you apply.

Mike