[GTO-relic]

that's cuz BG had released stuff like this....
750 baseplate with 2 different venturi sizes,
850 baseplate with 4 different venturi sizes
850 baseplate with 2 different venturis, and annular boosters.
that's only one line, the GC RS
general competition, removable sleeve

there also was Drag Race DR, Road Race RR, Tunnel Ram TR, Oval Track OT, Blower Carb BC lines, and 4 Alky lines.
fixed venturi, or removable sleeve.
a total of 80 different RACE carburetors, using 750/850 baseplates, all custom tailored metering to specific engine combinations, based on CID, cam timing, compression.
650-1050 cfm range
Holley wasn't even on the same floor, or in the same building as BG.
in addition, there was the King Demon Dominators, and Road Demon/Street Demon carbs with traditional choke horns.
every tuning spec was published for easy reference, for every single carb.