The difference fealt in the pedal would be almost unnoticeable. To get a serious performance upgrade, the entire intake/valvetrain/exhaust system must be addressed. If you intend to address all the other systems, take the time to plan out an entire combination. Save your money, read, plan, then choose a balanced combination of parts that work toward a certain performance level.
There just isn't anything out there that is really more simplier to tune than the OEM carb. Now I don't want the Edelbrock fans to take this the wrong way, because it is not meant as such....but, although the Edelbrock is a decent carb, it is nothing special...just an updated, polished Carter AFB unit from the 60's as far as style/design factors. For those who just want to bolt on a carb without having to touch it (change jets) it's fine for an OEM replacement type carb that has some refinements to it. For less money, you can take your carb to a carb shop (Culver City Carburator Company, Culver City Ca. example), provide them with all the info on your car, the way you drive it, any problems you are having and they will rebuild the carb like new and pre-adjust it to where with just a couple of turns of the external fuel mixture screws & idle speed, it will be an out-of-the-box set-up! that runs as good if not better than most of the aftermarket carbs.
I have to disagree with the previous posters. A properly-sized 4V setup is going to give noticeably improved throttle response versus a stock 2V. I've put 4V setups on a lot of otherwise stock 289-2V motors and I've always been pleased with the results. The most important thing is to not go too big with the carb. The 4100 or the 500 cfm Edelbrock would be my choice. It's such a pleasant feeling when the secondaries kick in.