Tim,
I have never seen inserts in a set of barrels, not saying that it is not a good fix, just saying I have not seen that particualr repair. I used to repair Pre-Unit jugs by tapping the head bolt threads over in SAE 3/8" - 24 fine thread.
Good inserts known as KeenSerts are excellent however, they come with some precautions also. Namely in drilling and tapping for the new insert. You will need to get the Helicoils out obviously, find a supplier of the KeenSerts, get the entire kit for drilling and tapping etc...
The other concern is whether there is room for the repair in the jugs.
http://www.newmantools.com/kee.htm
The first thing that you will need to is determine also which thread and pitch you are going to go with, it will not be Whitworth BTW, insure that you can find these bolts at the proper length and grade, then et the KeenSerts kit.
Not at all surprising that the '54 T100 alloy jugs suffered pulled threads but they can be repaired with care.
Also, Be sure not to just tighten the bolts up rather torque them to spec.
Good play with the annealing of the gasket....
Anyway, the Keen Certs (IMO) will be better than the Helicoils that can move in the threaded hole which is not good.
Best,
Rob
