My oil burning pig. Pics too!

Ironmike - I hope you get this worked out, very nice looking car and motor. As I said earlier, I wouldn't dismiss the intake gasket as a cause. But you apparently have eliminated it. That leads to valve seals/guides in my opinion.

I wish I had my info at hand, but nothing is available to me right now. I just wanted to point out that the PC type plastic seal may not be your only option. I last used a combination rubber/plastic insert seal with dual springs on my last stroker build. It gives the same tight seal around the stem with a tight rubber interference fit/mount to to the valve guide as does the PC type seal and fits inside the dual spring.

I want to say it was made by "Pioneer"? with an OS part number or something like that. I think I came across this seal from Herb McCandless or Henseley or someone in the know. All I know is I really liked it. It allows the seal to flex sideways with the valve stem no matter the clearance, is anchored to the valve guide (unlike an umbrella seal) but still hugs the valve stem as tight as the plastic seal with its plastic insert.

As I said, I wish I had the company name/part number at hand but I don't right now. I do have it though. I would like to see you get this solved. Hope this helps.