[unstable bob gable]

Well, I have a set of aftermarket valve covers on my AMX, and they are big, cast alum jobbies. Well, when I put them on the first time with just a plain Fel-Pro rubber gasket, I had a leak on the driver's side. I took the cover off, cleaned up the gasket, skimmed it with some Permatex "Right Stuff," and re installed it. It seemed to hold up fine, until sometime in Dec, when I went to start the car up and run it a bit while it is in winter storage. The driver's side started leaking again, so I said "F" it and put the car away. Welp, it was nice today, so I figured I'd go run the car, and see about the leak. Some of the bolts were loose [I'm using stainless Allen bolts], so I tightened them up, and the leak seemed to be taken care of. I drove the car around a bit, and when I came to a stop at a light I noticed smoke coming out from under the car. I got back to my storage garage, and the valve cover was REALLY leaking badly. I tried tightening up the bolts again, but no dice. So I put the car away. Now I'm looking for a fix...and since I already tried my usually "proven" method of gasket and Right Stuff and it didn't hold, I'm looking for ideas...