So I dunked the spare carb I found in the garage last week into a tub of Simple Brown (thus named because it previously was used to clean one of the Thermoquads) and let it soak overnight. I was curious to see what it was because A. I can barely remember where it came from, and B. I wondered if it might be a simpler 4-barrel replacement for the Thermoquad I’m currently running. I scrubbed it off with a toothbrush this afternoon to reveal the stamping number, which identified it as a Holley 2100C for a ’73-’75 IH 304/345 gas motor. Doing a little digging online and in my brain, I remember that these were not highly regarded carbs, and the garb guru I remember from the Chewbacca era describes it as a smogged carb with limited parts availability, which is a double-bummer. So I’ll probably fool around with it for a while and see what makes it tick, and then toss it in with the other junk parts. The next one to identify is the one on the spare 345 out in the garage—actually, maybe I’ll swap these two out so that I can bring that one in here and clean it up.