Broken? parts 63 700 84 hp

[Torkwrencher]

Crack at mounting post

Crack at mounting post

So, I am working on getting the engine cleaned up and going over all the parts/pieces and details. Check the photos on the thermostats, one has a crack in the solder going all the way around. Is this a critical flaw? Can it be soldered back together without destroying the whole thing or is this a non fatal, it should be okay for another 20k miles kind of flaw? The next broken item is the choke pull off, it snapped off right above the connector for the lower choke rod, it is very small so I doubt I can drill and tap it out and don't have a welder to plop a bead on the top of it. Clark's is out of stock for the 63 style and apparently the 64+ style requires replacement of the actual choke coil...So does anyone have a 63 style rod or a full 64+ rod and choke coil? Next broken item, while cleaning the head studs in preparation to replace o-rings, valve cover gaskets and pan gasket, I noticed that all of the protruding threads on one of the studs is gone. Will have to replace at least this one stud. The question on this: "Keep Your Corvair Alive Book" and numerous other posts say not to let the studs turn out of the block. Is it okay to spin this stud out by itself using the rusty nut or should I split the nut and vice grip out the remaining stud when it has no load on it?

Here is the history
1963 700
61k miles
Sitting since 1981
84 hp engine, I don't think it has ever been apart or touched it is very dirty.