Coolant leaking out of valve cover hole?

[dagit]

i just recently started giving my 68 289 some needed attention. it needed a new carb. so while i had it off i took off my intake manifold and repainted it. after reassembling everything its been like 4 months since she last ran. well i got her started today and it sounded rough. there was a little bit of clacking so i decided to take off the valve covers and spray some lube to try to get the valves from sticking. well as im unscrewing the front bolt of the valve cover coolant started to come out of the hole! Im getting freaked out thinking i blew a head gasket or something but theres no coolant in the oil. also it was coming out like it was under a little pressure. i took a shop vac and sucked it out till it stopped. im really confused because i've taken the valve covers off in the past and i don't remember this happening. If any one knows if the bolt hole hits into the cooling system or any other insight on this would be much appreciated.