Noticed some oil (quite a bit) on no.7 plug and there is evidence of leaking on the exhaust valve stem (had the headers off).

Wondering if it is worthwhile working on this in the car? (I think its only the one seal that's giving me trouble) or should I yank the engine and do the whole lot?

Never done this type of work before, but reading up on it it doesn't seem too difficult, even for a noob like myself.

Thanks in advance,