The 0.98 is the smallest venturi that motorcraft/autolite produced in the two barrel carburetors.
Here are the venturi sizes available:
Autolite 2100 Sizes and Applications
.98 Venturi(190 CFM): 221 Windsor
1.01 Venturi(240 CFM): 260 Windsor
1.02 Venturi(245 CFM): 289 Windsor, 272, 292 Y Block
1.08 Venturi(287 CFM): 289 Windsor, 302 Windsor
1.14 Venturi(300 CFM): 289 Windsor, 312 Y Block, 332, 352 FE
1.21 Venturi(351 CFM): 351 Windsor
1.23 Venturi(356 CFM): 352 FE, 390 FE
1.33 Venturi(424 CFM): 390 FE
My motor is 2208cc, at 75% Volumetric efficiency.... the user % VE is 166.671 CFM. This will mean that the 1.01 venturi carb is about 80CFM too large.
I've been told that the CFM of the carb doesnt really matter, because you can regulate how much it flows by how much you put your foot into it.
Is this really true?