Early Autolite 2100 2 BBL carb with 1.01 in venturi's. I tried this on my hopped up Model A engine but never got it to work. Has a broken post for mounting automatic choke. I made a manual choke adapter of sorts. The air cleaner hold down threaded rod is just a 1/4-20 all thread as the original hole was damaged. I rebuilt the carb and I have a couple sizes of jets for it that will go with the carb. These are hard to find in the smaller venturi size. They originally came on the late Y-blocks (earlier version of this carb) and early small blocks (221, 260). There is only one size smaller venturi out there if you can find one (0.98). So if you need the small 2100, here you go.