Oil burn diagnosis (minor)

[saki302]

Hello, I hope everyone is surviving quarantine!

My car with the roush 427r puffs a little oil smoke from the passenger side when revving from idle (slight). I only noticed it while watching a drive by video on the track, it puffed a little smoke as I did a high rev hard acceleration shift from 1-2 gear.

It's not terrible, but I'm a bit OCD so I will chase this stuff until it's either too expensive or impractical to fix

I pulled each spark plug on that side- they all looked fine except plug #8, passenger side rear. After a track day and a couple hundred miles it was slightly oily.

From researching it, it looks like one of three things, one easy (valve guide oil seal(s)), one easy-ish (infamous roush intake manifold gasket failure), and one.. never mind (piston oil control ring).

Based on the symptoms of a light puff on a shift after a hard acceleration, and wispy puffs on rev up in neutral from idle (cold or hot it seems), what do you think the likely cause is?

I went into the intake with my janky Chinese bore scope, and the intake valve of #8 does look like it has more carbony/sooty crap on it versus the other cylinders. I'm leaning toward valve seal or infamous intake gasket. Keep in mind the bore scope kind of sucks, so visual field isn't great. It took some wrangling to get it in position to focus on the valve.

Thanks!

-Dave

P.S.- this and my leaky oil pan gasket I plan to swap with Moroso at the next oil change are hopefully the last things before I just enjoy driving the car. I'll have to rebalance the wheels too.
The pan gasket (I swapped a Fel Pro 1Pc) drives me nuts- it doesn't leak much if at all if you go for an immediate drive, but will leak a few drops if you idle it around and don't take it out. Like an SR71, leaks cold, seals hot :P