It's not the external crack that's causing the smoke.
Something else is going on. Rings, valve stem seals, we don't really know that yet. That's why we want to see it run awhile as in at least a couple tanks of gas through it.
I had an old Avanti 289 that smoked like california this summer
but after running MMO through the gas as well as in the oil and a couple soaking periods with it in the cylinders it eventually cleared up enough that I could see out the rear view mirror
. It smoked about like yours in the end.
My point is old engines go through their ups and downs when they've sat for long periods of time. Like achy joints loosen up after moving around and we/I want to see how much it changes after you get it going down the road not just 'awake' in the driveway.
