Valve cover leaks...

[FloridaRebel01]

Just got a 91 GM with 69,000 miles a few weeks ago, been driving it around town for a while and it runs real smooth with no ticks or clunks or anything. Its leaking oil from the valve covers and getting on the manifolds and causing a little bit of smoke (and it gets smelly in the cabin).
Question is, since im going to be installing some valve cover gaskets in it (seems pretty easy according to the manual), is there anything else i should be replacing while im in there? should i go ahead and reaplace the head and manifold gaskets as well? if im missing anything let me know, just trying to get it to be a good daily driver.

[pantera77]

Pretty much any and all vacuum lines while you have the upper intake off, and the pcv valve, grommet, and screen.

Do not use cork gasket's on the valve covers. Spend a little extra and get the rubber/steel ones (preferably Felpro Permadrys).

[johnunit]

I wouldn't bother with head or even intake to head/block gaskets. Head gaskets are not a common failure point, and intake gaskets are just best left unfuckedwith if you can.

Do what Pantera said.

Also take a look with a straight edge against the sealing surface of the valve covers, and make sure it's not indented (pushed close to the head surface) around the boltholes. Often this happens when someone re-tightens the bolts to try and fix a leak, when the gaskets are really all crumbled. Once this happens, you need to straighten the sealing surface out, at least so that it's not visible by eyeballing it, or you won't seal the valve cover mating surface. A HUGE +1 on the rubber gaskets. The permadries have a neat little metal ring around the bolthole which helps prevent the aformention warping problem. Downside is that it will not be able to mask an already warped cover as much.

[85crownHPP]

You have it a bit easier since its a 90-91, the fragile plastic vacuum lines are a bit easier to deal with when you remove the upper intake manifold.
If you want, you can also replace the injector 0-rings while you're at it, they are known to leak.

[FloridaRebel01]

Thanks so much for all the info so far, much appreciated.