I didn't spend much time on this, went through about 25 percent of the W-1 stuff currently on ebay:

115647114670
115424715545
154606995498

Used cores, all

Didn't look for rebuilts, but I wouldn't look for rebuilts on ebay.

Jon.

Good carburetion is fuelish hot air
The most expensive carburetor is the wrong one you attempt to modify.
If you truly believe "one size fits all," try walking a mile in your spouse's shoes!
The Carburetor Shop