I’m guessing the umbrella type seals helped with bypassing oil vapor. The umbrellas were not staying on the guide boss but going up and down with the valve. All the piston tops were carboned up and had to me looked slightly wet which I wire brush cleaned. Plugs were ok and I use that type of seal on all my racing GMC 6’s so I figured why not. The guides and valves showed no wear after micing the id of the guides and the od of the valves. In November it will be a year and I’m going to look in each hole with our sons camera, I’ll have about 1500 miles then. All I can add is sitting at an intersection idling in gear if I didn’t have a tachometer I would not know the engine is running. My wife even commented on how smooth and quiet the car is. We have a stock cam and stock 3 tunnel style mufflers.