I would agree with LA.
Before you worry about a stroker or other changes give your 350 a chance.
Check the basics, plugs wires cap rotor, check/set timing, etc.
While you have the plugs out, run a compression check. If everything is working right that 350 should sound good and pull strong. If not, your engine may need a ring and valve rebuild which would be a good time to consider a few choice upgrades especially for things you would replace anyway like the cam.
Keep in mind that the car may have a 256 or 273 gear (common on early 70s A bodies), less kick but plenty of mph. 373 gears would give you more than boring out, for less money. Keep in mind that the Pontiac 350 doesn't scream like a sbc, it uses that long stroke to produce torque.