Smoke coming from driver side pipe - Good and bad news

[Fman]

Hi all, hope everyone is doing well...

Looking for some insight on what this problem could be, I am just a weekend hack mechanic on my best day so any guidance or input would be appreciated!

My car was completed back in April 2021, has 6500 miles on a dart block 427, EFI. Oil has been changed approx every 1000-1500 miles (annually). Car has always run great, no overheating issues, good oil pressure, etc... Recently over the past couple weeks I have noticed smoke out the drivers side pipe when accelerating and decelerating at higher rpms. The passenger side pipe is completely clear. If the car sits over night I will also get a brief puff of smoke upon a cold start out only the drivers side pipe. Once engine is running when idling there seems to be no smoke at all. The color of the smoke is blue-ish, definitely contains oil (see troubleshooting below). Passenger side pipe is always clean in all driving circumstances.

Ok, so here is what I have done so far.

Pulled all the plugs - The drivers side were in terrible condition, black, gummed with oil residue (see pics below). Infact I was shocked the car was actually even able to run. The passenger side also looked like it has heavy carbon on them definitely on the rich side. I am assuming these plug conditions indicate oil getting into the cylinders and burning off.

Replaced all the plugs with Autolite 3924's (what was installed by my engine builder)

Compression test - All cylinders came back at 210-220 psi

Intake manifold - Checked all bolts, they were definitely loose (under 10 ft lbs). Re torqued to 22 ft lbs.

PCV - Eliminated it, now just running two breather caps and plugged off the intake port where PCV was previously hooked up.

Went for a test drive this morning and same results, nothing has changed with the above tweaks. Car runs fine just smokes out drivers side pipe as described above.

My next move is to do a leak down test this week, have the tool on order.

I am hopeful it is not bad rings but my gut is telling me this might be the problem seeing as it happens under hard accelleration and deceleration. My other take is could it be the intake manifold (seeing as bolts were loose) is somehow allowing oil to enter into the valves/cylinder, and then there is also valve guide stem seals. What is really odd to me is how its only happening on one side of the car. If anyone has any constructive input/recommendations they could give me I am all ears. At this point I feel like the leak down test will give me some more information.

Thanks for reading.... Travis

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