[fordteacherguy]

Jim, here is a copy from a Ford forum.

The autolite 2100 (2 Barrel) came in sizes ranging from 190 to over 400cfm. They have an engineering number cast into the body that identifies the size. There is a clock face cast into the right side of the carburetor. The carburetor size can be found right in this clock face. For example with 1.12 cast into the aluminum; the 1.12 indicates venturi size.

According to the Ford Carburetor Guide from Pony Carburetors, flow figures for the Autolite 2100 carbs are as follows:
.98 venturi = 190cfm
1.01 = 245
1.02 = 240
1.08 = 287
1.14 = 300
1.21 = 351
1.23 = 356
1.33 = 424