Stock 318 bolt on performance modifications

As I'm pulling parts off this 1975 Valiant 318 to transplant it from a four door parts car to a 72 slant 6 Swinger. I'm wondering if it would be worth it to add headers, intake, and a small four barrel carburetor.

I'm actually fine running the motor as is with the 2 barrel carburetor and stock exhaust. This car is just going to be a cruiser, but if I could increase mileage or Hp noticeably. I have an open mind and a small budget.:D

Any input from the 318 guys? Remember this would just be a couple bolt on items. Were not talking about getting into the engine.

Carb and intake will make a nice upgrade as far as performance. Shouldn't be too expensive either. Keep your eye out for a used Eddy Performer and a 600cfm Holley/Edelbrock. To save a few more bucks, i'd run a nice dual exhaust off the stock manifolds, much less hassle. Run as much initial timing as you can and it should be a nice cruising package and get as good or better mileage then stock. Jmo.