You may not have seen that Stromberg U2 carb reproductions (the three main parts) are available for a limited time from Antique and Classic Reproductions out of Australia. They are cast in aluminum and you transfer your old internal parts to the new carb. That's not hard to do if you work methodically and take pictures as you go. This business is shutting down within a few months unless someone buys their patterns and continues on. Address is in the forum.
You can also purchase a new Zenith carb from most tractor supply outlets.
The Zenith model 267 sub model 14991 will work.
You can also find a good used or rebuilt Carter BB-1 carburetor.
The Stromberg is your performance carb and as Ross said you can buy a new housing and reuse your internal parts.
But move fast, as they will be closing over the next couple of months.