Well, if the car is original, then DEFINITELY mark & keep all the original parts. I would suggest headers, a dual plane aluminum intake manifold (check vs. hood clearance since they are usually taller than stock) and a high-flow air filter first while keeping the stock carburetor. Next, I'd probably add electronic ignition and see where you're at.
Assuming the engine is low mileage (say 50,000 or less) a cam is a good idea, but keep in mind you'll need a new timing chain, valve springs, lifters & maybe rocker arms and pushrods too depending on the cam. Honestly, you might be best off doing the "bolt on" stuff I listed above & then build an entirely new motor for the "hot rod upgrade". I like taking that approach myself with cars because you can pull out/replace an entire engine in a few days and still have a complete "backup engine" (the one you pull out that's still complete). If you rebuild the one that's in there, plan on at least a month or two extra time with the car not running while you wait for machine work to get done & parts to come in, etc. This approach is also a good idea if the engine in the car now is the original engine.