wow, they must have let some really corrosive fuel sit in that carb, it ate up the bowl and the bottom of the mount tube.
are you going to get a ball wire brush and put it in the drill to get all the junk out or just get another carb? the rest of the carb looks ok.
i like rebuilding carbs. i used to go to the junkyard and find odd carbs just to take apart and rebuild. down draft, side draft, up draft, one through four barrel, anything, i like rebuilding carbs.
most people hate chevy quadrajet carbs but if you actually know how to set them, they are great for daily and off road use. i rebuilt the original quadrajet on my 79 chevy with the 350 v8 and got it to get 14mpg on the highway. it was a 79 chevy heavy half with the stepside short bed, 350 v8 and an automatic transmission. rebuilding that carb and tuning it properly with a vacuum gage made it feel like a new truck.