You will need special tools and whatnot to install the cam. It's better to have a machine shop install the cam if you have never done it before. This is not a good time to experiment. As far as cam selection is concerned you have to make many decisions.
www.summitracing.com has a general guideline to cam selection regarding what you want out of the engine. I would not go too bumpy as the 383 will give you ample grunt stock. Switching to a single carb setup is a wise decision as it will give you better performance and mileage for the realistic type of driving you will daily encounter. A dual carb setup is overkill and useless in most daily driving. I'm a big fan of RV cams as they offer excellent torque and smooth grunt off the line. They give the big engines effortless and smooth power.