For a fun experiment I would like to bore a .335 driver head to .350 and use a clock ferrule to adjust the head a little more closed.
Appreciate you weighing in with experiences and/or willing to buy one if anyone has one laying around.
I don't have one but have used them. They work, at least within the limit of the design.
I experimented with that years ago. I didn't bore out a driver head, but had a couple that were already .350 and one maybe have been more like .400. I don't recall if I bought ferrules from Golfsmith or Golfworks as it was that long ago that Golfsmith still had a lot of clubmaking supplies. I remember it being marginally successful with what I think was an old Adams driver head.
I'm sure Billy Bob's would have something.