Valve guide or valve seal?

[Hozer 88GTConv]

did you have any indications before you discovered this?
Specifically, was oil saturating the threads of a plug?
Or was it just enough oil to get thru that would rapidly burn off and not even yield the dreaded death smoke?

I have no smoke at all, I mean none, despite what appears to be a consistent oil leak into #5 somehow.

I am going to do a partial tear-down this weekend and check the valve seal. I couldn't do it before because I didn't have a functioning spring compressor.

Thanks again...followed by a leak-down