Positive seals are engineered to meter a small amount of oil down the valve guide to keep it lubricated. If you choose to use them, it's best NOT to also install the O ring seal under the split keepers. I only use positive seals on intake valves, and stay with the O rings and the sheet metal deflectors under the spring retainers on the exhaust valves. The intake guides are subjected to manifold vacuum on the underside, which justifies the positive seals, IMHO.
Jerry
