Keep a stock carb or upgrade?

Is it better to stick with an original Rochester carb on a 322 nailhead as opposed to using a 600cfm Carter with an adapter plate? Some have told me to do the upgrade though I may have to plug some exhaust holes and install a secondary starter under the dash if I use an adapter and others say stick with the original if I can and that the old Rochesters ran great. This is on my 55 buick special. What do you think?
Thanks!

 

If there is nothing wrong with the orignal that a kit won't fix keep it. With the Dynaflow ya ain't going for performance any whoo.