There's a very simple fix, one that was used during the development of the Quadrajet. Those carbs have a small spring that keeps the metering rod pressed against the jet, preventing it from wobbling (or spinning, in the case or the QJ) that wore jets out and even damaged the casting the jet was threaded into. Metering rods don't have to be centered in the jet to control the volume that goes through it.
Instead of going to the trouble to make a press-fit "jet" why not just thread the carburetor body to accept Holley jets? They're plentiful, cheap, and come in all sorts of sizes. I've got a couple of hundred of them left over from my round track racing days.
Jerry
