BB wowbagger

Rubber :cheers:

Smokehouse69

I really don't think it matters too much as long as the gaskets are put on straight and the valve covers aren't warped. A big mistake I used to make was over-torqueing the gaskets.
I have personally had really good luck with silicon rubber gaskets, they are put on dry and remain flexible after repeated uses.
For the silicon rubber gaskets the hardest part is getting the to stay in one place while you are installing the covers. They are so flexible that they have a tendency to creep or squeeze out of position unless you "tack" them in place. To do this clean the gasket groove in the cover with break cleaner and use tiny dots of some sort of adhesive to hold it in place, then re-install the cover and bolt it down.
Another thing that helps is to use load spreading bolt retainers. They are cheap and apply much more even pressure around the edge of the covers.
Retainers are available from Jeg's and Summit and probably a lot of autoparts stores, they are about 3" to 4" long and replace the small retainers used on Chevy sheet metal covers.
Cork gaskets are okay, but they get hard and crumble after getting hot over the years.

joeveto

I used rubber, no sealant. Worked great. No leaks.

vettfixr

Ditto on the rubber. When you put them on make sure that your valve cover bolts don't bottom out because the gaskets are thinner than some of the cork ones out there. My bolts were too long and didn't compress the gasket correctly. I had a leak for almost a year that looked like a rear main seal until I accidently bumped the valve cover one day and saw it move.

Chuck Gongloff

Cork!! I like cork gaskets. Clean the valve covers well. Make sure they're not bent. Metal-smith them back straight, especially if they've been overtightened around the screw hole. Use permatex to "glue" the gasket to the valve cover. Use bolts and nuts to align the holes. Let them dry for a day. Then put them on without any goo on the head side. Has worked well for me for decades. The rubber ones are HARD to keep in place...they slip and slide. Chuck

Flareside

I'm a cork guy too. They both work ok, but the cork is a little easier to keep in place.

redvetracr

I swear by the cork gaskets with the steel shim in the middle, they are the BEST!! ...redvetracr

Chris O'

Rubber, rubber, rubber! Use a bit of RTV on the valve cover side to keep it in place and enjoy a leak free motor (from that part anyway :) ).

I have the Fel Pro rubber gaskets and they are great!

:cheers:

Turbo-Jet

Rubber will not often work on stamped steel valve covers. Too stiff.

thejaf

Screw-in studs instead of the standard cover bolts. This aligns and keeps the gaskset from moving around on you. Also, use thicker cork, it holds shape better.

vettesite

I do the same and my Vette has no leaks.

UKPaul

I swapped to rubber as a pair came with my new alloy covers (thanks VettePaul :) ). Since having them, when I pull into my garage after a long run, there is a smell of cooking/burning rubber coming from under the hood. I've checked all hoses, etc, etc several times & found no hint of any problems. Does anybody else get any strange smells when using rubber ones?
:cheers:

wallyknoch

I agree, your procedure for installing the gaskets are correct. Never use blue goo or anything similar. I would recommend using the yellow or black weatherstrip cement as the primary sealer. Just clean the overhead cover spread some of the cement [3M] is a good one, on the cover. Let it get tacky and place the gasket down into the cover. I personally place some objects on the gasket to make sure it stays straight. In about 15 minutes its dry and ready to put on. The beauty of this is you can move the cover around without the worry of the gasket being on straight. or bumping a rocker arm and moving the gasket. Some wheel bearing grease on the head side will help preventing the gasket from sticking to the heads. Another thing, is you can use them over and over. One note however, the modified gasket consisting of both cork and rubber is very flexible and probably the better choice as a pure cork gasket gets brittle. I have been using the same gaskets on my valve covers on all my engines for years without the necessity to buy new ones. :cool: :cool: :cheers:

MotorHead

I use the thick cork gasket and use Permatex #2 on the valve cover side to hold them in place and nothing on the motor side that way when you take the valve cover off the gasket stays on the cover and you can reuse it as many times as you like. :D