Headers and a good exhaust will make a little difference and are a good starting point for performance.
A bigger carb might make a small difference at high rpm but most likely will either make no difference at all or it could even reduce performance by making the throttle response poor.
How good is your engine now? Are the pistons a good fit in the cylinders and making good pressure? Burning any oil?
It is no good fitting performace parts to a worn engine.
There are two good ways to go about this.
The first is to decide how much power you want and design a 'package' around that. Bear in mind that the more power you have, the more undriveable the car will be on the street.
Another good way to go about this is to decide how much you want to spend and work around that budget.
It is no good us telling you to fit Edelbrock heads and high compression pistons if your budget is only $500
If you want to make real power you can find it this way.
How much power you make is decided by how much fuel and air mixture you burn.
How much mixture your engine can take in is decided by the cylinder heads and the camshaft. These two are the bits that make the power.
The intake and carb are then selected to match those other parts. Your gears in the axle have to match the power band of the engine too. Your transmission may need to be re-built with performance in mind and you will also need a higher stall torque converter that matches the engine output.
So the more power you want to make the more it effects the rest of the car.
But 350hp is not a huge amount to ask of your engine and could be done with mostly stock parts.