Re: stripped crankshaft harmonic balancer bolt
up front, the balancer is a press fit on the crank, the bolt is a safety device. Early SBs weren't even drilled for a bolt. BBs are famous for having a really tight press fit on the balancer. Often normal pullers break before moving them, etc.
Now, unless you are a highly skilled and tooled up guy or you know somebody who is the chances of getting that properly repaired with crank in the engine are about zero, zip, nada and all that. I'm not saying it can't be done, but there's a good chance of ending up worse off that you are now. The hole need to be drilled oversize and a long heli-coil installed or just drilled to the next size and tapped. Either way the drilling must be dead straight in all respects and the chances of doing this in the car with a hand held drill are slim, IMO. Best way would be to pull the crank and do it in a lathe.
One thing you could do is investigate whether the existing bolt is too short and pulled the first few threads. In that case there might enough threads left in the bottom of the hole for a longer bolt to grab. Have to be careful not to get one too long and bottom it out in the hole.