Race Demon questions

I have a 750 Race Demon. Works great. It's on my 64 Sport Fury 440/ fmvb 727/ 3.91 rear. 3k stall convertor. I was told a long time ago that the race demon was rated smaller than they really are. Like my 750 would be an 800cfm. Is this true? How would this carb work on a 500 ci stroker? Also, I was expecting to see that air idle adjustment in the center of the carb when I rebuilt it. There was a plug in there instead. anyone have any thoughts? My questions are for a race demon only. Seems they don't offer this carb anymore.