Thought i'd update...
Machinist said everything was a GO, the cracks around the head bolt seats weren't critical, and that the block is sound otherwise. So I had him bore it out (.040), deck it, and install new brass expansion plugs.
The head also checked out, so I had him install new valve seals, valve job, surface it, etc.
Crank just got a polish.
Got all the new parts in; Pistons, timing components, gaskets, bearings, rings, etc.
Everything went together as planned. I continuously second guessed myself, because everything was just so simple (in comparison to other projects i've done in the past). I primed the oiling system by removing the spark plugs, and cranking it over for a few minutes. Then fired it up... or attempted to. It hadn't occurred to me that the distributor is not "keyed" like most newer cars. It's been a while since I've worked on something this old
After a few backfires, I figured it out. Sorted it, and it fired right up.
After running it a while I took it for a gentle test run. All was well, aside for a little necessary carb tuning. Then a coolant leak developed from somewhere. It was very difficult to track down, as it was dripping from the bell-housing. Long story short: I have an exterior crack in the block on the passenger side, connecting the front-most and middle expansion plugs.... Gotta love it.
Still waiting on a call back from the machinist...
In a desperate attempt, I took the recommendation of my wife to find a "special glue" to patch it up. I went down to the local NAPA and got a bottle of Blue Devil block sealer...
Now let me preface this by saying that buying and trying something like this, is the absolute last thing I would ever resort to. I'm always a proponent of fixing something the correct way, or not at all. But in THIS case, I thought I had done just that, only to find that due diligence was not thoroughly performed.
So I follow the directions, get it in my cooling system, and it starts seeping from the crack. After about fifteen minutes or so, the crack turns greenish white (from blue), then white. And the leaking ceases! I shut everything down and check the coolant to make sure that this hardening is not systemic. Everything flowing good.
It's been two days now. Coolant level static. Temps good and cool (even on highway). unbelievable... But I don't yet trust it to hold for good.
In the meantime I'm researching possible repairs, and I've come to stitching (due to the block being cast iron). Anyone have experience doing this? Looks pretty straight forward, but more research is needed.