I thought the 9000 series AFBs were all aftermarket?
I remember buying a few (forgot which) either 9626 or 9636s about 20 years ago.
I dug out my S&A book on these carbs by Dave Emanuel and that's what it says
Ending in 0 or 5 was GM application ending in 1 or 6 is Mopar and carb number ending in 2 or 7 was the same carb again only with a ford throttle linkage setup.
I can see where they would have possibly had a "target engine" to calibrate towards a typical customer who would buy a certain carb.
One thing I noticed a little weird between the 9511 I have here and the 9626 I have here, is that the butterflies seem to be the same size in both, so how can one only be rated at 500 and the other as a 625?