It worked on an undamaged prechamber on my 300k miles merc. I wanted one of those bicycle hub pullers because they were cheap. It was from baum tool and came with a slide hammer. The threads on the tool are bad enough that I would never use on a good prechamber, but their still pretty good. Its the prechamber itself that is mangled.

I am holding off on doing anything today (50 minute round trip to get to the car). Do you think I should reuse my home made chaser to get the threads in the best possible shape? I could try to acquire a tap, but my thinking is that might be worse at this stage. Use something better than JBweld. I stupidly have used the quick version in the past and was not impressed.
Things better than JB weld:
1. "autobody panel adhesive"
2. Loctite 324 industrial adhesive $20 for a small bottle and another $30 for the Loctite 7075 spray activator
3. Couple of spots of 3M 4200 UV cure to hold while a nice bead of 3m 5200 sets, maybe $12 a tube each (urethane). Urethane is used to join body parts in production, and it is generally more flexible than epoxy. I have heard than urethane glued body joints can be stronger than the steel they join.
4. Based on my experience of fixing stuff that seemed nearly hopeless, I would recommend PC7

I am leaning to the 3M 5200 because its got some flex and might be less likely to break with slide hammering? (what do I know). 7 days to set though! Suggestions anyone.