My first 2bbl to 4bbl swap.. scratching my head..

So i recently (last friday) bought a 71 plymouth scamp off of my uncle. It has a mild cam(unknown specs) heddman headers and 3in dual exhaust the whole way back. I helped him put all this stuff in about 5 years ago, now i own the vehicle. the problem i have is its still the stock manifold and 2bblcarb in there.
It hesitates and feels like its not getting enough fuel on take off. Its an everyday back and forth to work driver so i dont want anything crazy. But i feel as tho it needs at least a 600cfm carb(i have an original holley 4bbl rebuilt). I was wondering how hard/easy of a process is it to switch things over to a 4bbl. I'm trying to do this on a budget considerin i just spent the money on the car. any help would be greatly appreciated. Curious about whether or not i need new springs, throttle linkage..etc. pretty new to this stuff so i'm trying not to screw up to badly. thanks in advanced!