Blow By

My slant has had blow by the entire time I've had it. (3 years) I've put on about 15,000 miles in that time.
Your muffler is probably full of carbon which is why you're not seeing it too bad from there.
Mine also runs like a champ at 70 mph. I've tried everything under the sun, re seating the rings, adjusting everything again and again. I think the rings are just bad and I am gonna pull it later this summer and rebuild it.