Kevin,
Here is what I do if it will help.
1. make sure the lips of the valve covers are flat and straight.
2. clean with starting fluid.
3. use thick cork gaskets.
4. gather the bolts that go through the covers
5. place a thin coating of RTV ( pick a color like black ) over the lip(s).
6. carefully place the gasket on the cover and press down.
7. use the bolts to align the gasket.
8. allow to dry.
9. apply a thin seal coat of RTV over the now attach gasket.
10. allow it to dry.
11. strange as this sounds, use a small torque wrench and tighten to 10 foot pounds as you install the covers.
These do not leak and can be pulled off a number of times. The coating on the gasket coupled with the 10 foot pounds should allow you to use this for a long time.
Hope this helps!
