It's always a lot of fun, planning a restoration, or a resto mod...My free advice, is have an overall goal for the car. Is it going to be a daily driver, or a weekend cruiser? Is it EVER going to see any race track, or just street performance? You can get a lot of stuff used on the local craigslist, but it gets very expensive, doing things twice over...If you aren't concerned about low E.T., then a new carb, intake with headers and dual exhaust will for sure help. If you are going to build a monster motor later, and rebuild the suspension to accommodate 500 lb ft of torque and price is no object, then go ahead and gut the car, and start shopping for a 429/460..
Before you change the gears in the rear end (that is a very good way to make the car "quick" off the line), you need to think about your overall goals. It doesn't make sense to change the rear gear, to find out your new cam requires a higher minimum gear.
The cam and rear gears work together, in order to get all the value out of your build.
For example, my 289 is a .030/.010 over and under, with a performer RPM cam, .496/.520 lift. I have a T5 trans, and a 3.50 rear gear.
the engine makes good power, and pulls very nicely with the 3.50, but as soon as I go for the OD, the car lugs.....If I had at least a 3.73 or a 3.89, I could still be "on cam' in 5th gear, while still maintaining a lower cruising RPM....Think about what you want to do with the car realistically, and then plan accordingly.