Basic 318 Mods

Wish me luck as I'm going to be checking out a couple of duster's next week. I'm only asking these questions as a quide, both are 318 cars but one is a 2 barrel. Once the car is home I'm going to check it out completely and if everything checks out okay I'd like to do a 4 barrel swap and was wondering what size carb and intake manifold to use. I thought about a better coil and module. A curve kit and a good dual exhaust system. The car will be a cruiser only and probably the engine will never see more than 4500 rpm's. I'm open to a stall converter and a different gear ratio. Maybe even a mild cam.
Like many here have said: drive it for a while to see how it can be improved. The teen in my Swinger is the stock 2 barrel. It runs so well from cold start to highway cruise that I am having a hard time pulling the trigger on the LD4B and 650 AVS2 that I have waiting in the basement. I cruise hours to a car show and get almost 20 mpg. It doesn't burn tires for a city block but I'm not into that any more.