A while back I purchased some fabricated valve covers and I also picked up some rubber gaskets that were supposedly for the fabricated valve covers. I installed them when the engine was out so I know I lined them up exactly and they had not slipped around. Before I had even driven the truck out of the driveway when I had the tranny problem, we discovered that the valve covers were leaking on the bottom rear corner, just a small weep but annoying on a nice clean and detailed engine.
The covers were tightened to spec and still leaks. Finally removed the gaskets and put a finger smear of RTV on the top and bottom of the gasket. Next day the same oil drip was on the pan. I then removed the valve covers again and installed the FelPro rubber ones that were on the truck before the bent push rod. They are a much better design, I guess I was just going on the thought that since the new ones were designed for fabricated covers they should be better for my application.
So far I have driven the truck about 30 miles on the better gaskets and they are not leaking, but time will tell.
Pic #1 leaky on on the left and Felpro on the right. Pic #2 you can see from the crease that is on the gasket that the stock SBC heads do not fit correctly on these gaskets. They just do not have enough meat in the corners to prevent leaks. Pic #3 where as the Felpro design has little ridges that direct oil that gets between the cover and the head back into the engine before it leaks out.
