o man thast gona be hared to get out right u can try soaking the screw in soem pb blaster or some bolt loosner stuff and get a left hand dril bit and drill it out if u can get it out u will half to get a nother carb off ebay
Oh yeah, forgot to mention that you are supposed to use wd40 to clean edelbrock carbs so that would probably be the safest option. I happen to have a stock carb I would sell for cheap, but it's missing a few small parts. You would have to substitute some **** off of yours onto mine.