The 1.02 venturi 2100 was stock on 292 Ford trucks up to 1964.  1.08s are better, and 1.14s used on Mustang 289s are also good.  Dont try to use anything larger.  Bolt pattern of 2100 and Holley 2300 is the same.  The best results comes with using models from 1965-1968 or 1969.  I just removed a 1970-74 Motocraft 1.08 2100 from my truck (forget exactly which year it is).  It worked very well.  Replaced it with a '65 Mustang 1.08 4100.

The Holley 2300s are also fine.  There are more of them, and they cost less either as cores or rebuilt. 

Mike, located in the Siskiyou mountains, Southern, OR 292 powered 1946 Ford 1/2 ton, '62 Mercury Meteor, '55 Country Squire (parting out), '64 Falcon, '54 Ford 600 tractor.

The FORD flat tops & Autolite's are good simple carb's

The venturi size is on the side of the float bowl. This flow info is from another posting, maybe this forum.

.98=190

1.01=240

1.o2=245

1.o8=287

1.14=300    

1.21=351

1.23=356

1.33=424  

A feature of these carb's is the annular fuel discharge ring, this help atomize the fuel.  I'm sure someone may have more detailed information.

I am wondering if the Autolite 2 barrels are any good or is the holley the one to have.  I have a manifold ment for an Autolite.  Are the bolt patterns different for the holley?  Does anyone know the flow rating for an Autolite.