"108" is actually "1.08" or the size of the venturis. The model is an Autolite 2100.
Tomco and Holley are companies that rebuild original equipment carburetors. If you get a rebuilt 2100 carb from Tomco or Holley, it may not be a 1.08" (287 cfm) carb. The 1.08 is the smallest version of the 2100. There were at least 3 or more sizes of the 2100 carb.
Someone else should be able to tell you what the 1.08" 2100 came on originally, if you don't want a larger version.