76 360 with Edelbrock manifold. I can clean this up and a few hours later it is back to some degree. I think it is coming from the bolts as I see no other place it can come from and the valve cover gaskets are new. Do these bolts have exposure to engine oil from below or are they blind holes?
Thanks

 

You are correct on your assumption,, Oil is weeping threw the threads.... R&R and put some thread sealer on them. That should fix it....

 

I wouldn't rule out the valve cover. Covers have been the source of many people doing many things such as rear mains when it was a valve cover. It's an easy fix to RR the cover gaskets with a dab of silicone sealer lightly all around both sides. Fish tanks seal up with it so can valve covers.

 

I had the same problem. It ended up being what I thought was a nice pair of aluminum valve covers. New gaskets didnt do it. Different valve covers fixed it.

 

Agreed, Some of the castings dont cut the knock for the intake runner, causing them to touch and not seat...

 

I will give that a try and get back on here. I did the valve covers a month ago and used a straight edge to get the covers as straight as possible. Cleaned the heck out of them and the surface below. It is not them.

 

As you can see I cleaned up everything, put thread sealer on each bolt. After looking at the holes I added the silicone. This has solved the issue.