personaly ive never had any luck with the Edelbrock line of carbs, seems like they will work fine for about a year or maybe 2 and then people start having problems (like flooding and rough idle)i get alot of chevys in my shop that have the Edelbrocks on them and with the warranty that Oreilly's has ,the folks usually have to go back and get a new one(and sometimes the new ones are crap too). ive had holleys for years on my cars with excellent performance but i went back to autolite factory carbs and they work great so far. my advise would be get ya a 650 holley vac sec. or even a demon. just remember you get what you pay for when your buyin a carb.
just for the record i run holleys on both my race cars 