Hi Charlie,
Now that I look at the photos again, I’m very surprised at the amount of build up shown on the valve.
Your engine is very “wet”
That’s not good, esp at 40 hours since overhaul.
If the streaks are indeed scratches in the cylinder walls, it’s a problem. For right now let’s assume that the oil control rings are faulty and that’s the reason there’s so much oil in the cylinders.
If the oil control rights were not installed correctly, or the gap in the rings is incorrect; that could be the source of all the oil in the cylinders.
Oil can bet into the combustion chambers and cylinders through loose valve guides, or lack of oil drainage from the rocker box covers, or improper rings (not too likely) or ring gaps.
Please take a couple of borescope pictures with the piston all the way back to the bottom of the stroke, while angling the camera/light back up toward the valves. I’d like to see both valves or as much as you can get of both valves as is possible. You may not be able to get a shot showing all of both the exhaust and intake valves, so please show all of the exhaust valve (the smaller valve) and as much of the intake valve as you’re able to fit into the frame.
Thanks,
Steve