Inliners International Forums General Discussion Engines Rochester "B" Carb sizes and cfm's

I think I've found an anomaly.
The usual rule is that the SAE flange size covers a specific range of throttle disc diameters with no overlap (the same throttle disc won't be available in 2 different flange bolt patterns).
Except: the 1951-52 Pontiac Model B is 1-1/4" SAE flange (2-11/16" like the 216), but 1-9/16" throttle disc (like the 1-1/2" SAE 235 & 261 but with 2-15/16" flange) and 1-5/16" venturi - a size not offered in that bolt pattern.
Looks like Pontiac has a space problem, or a lot of manifolds already made with SAE 1-1/4"? Misprint in the official Delco sheet?