crap. im gonna say its junk and needs a new to you engine. that much oil in the exhaust is death. way more issues then valve seals. its like a piston is missing.

have you changed the oil yet? it might have a pan full of chunks. aka the missing piston.

you could do a compression test, but im willing to bet one cylinder is really dead. likely a middle one too. front or back. heat samich there.