No misfires. Embarrassingly, I seem to have misdiagnosed the problem.

Instead of doing the oil change myself, I took the Disco to an oil change shop and they seem to have filled it with synthetic 0W40 instead of conventional 10W40 oil.

What I assumed was coolant in the oil may have just been thin synthetic oil.

...so I'm wondering if that synthetic oil leaked through gaskets at first causing the exhaust smoke?

Anyway, the Disco 2 is driving great. No overheating and now the exhaust smoke is gone. Can gaskets get accustomed to synthetic and stop leaking on their own after enough use? ...or maybe they slightly overfilled the oil??

 

This is great news! A misdiagnosis is the best result. Can't help you with your questions, but it is great to hear she is ok after all of the time and effort you have put into that engine.

 

 

Quick update, after 11,000+ miles, the AirTex waterpump failed.

OK, "failed" might be too harsh. Coolant temps are still being maintained, but the pulley has wobble, squeaks, and there is clearly load on the main drive belt.

I'm thinking that I might as well go generic and cheap on this replacement waterpump if I'm going to have to replace every 11,000 miles, so no more AirTex. Sigh...