I would start by putting a little bit of oil in each cylinder and rotating the engine by hand, to help lubricate the rings and build compression . Also change the oil & filter, new spark plugs, cap rotor & points, replace the thermostat and any rubber hoses that look bad, and flush out the radiator. I also would put in some fresh gas and replace the battery if it's really old. From there I would start the car and let it run for awhile so the fluids circulate, and then drive it around the block very easily. From there I would look for any leaks or issues that might occur and then fix as necessary.
As well as the three good answers you already have,if the engine hasn't been rotated in 12 years,you could have flat spots on bearings and cam.Would be extra careful when you first drive it.Hook up a good mechanical oil gauge to keep an eye on it.
the 350 came as a standard option for that car. if it has not been started in 12 years then my professional opinion, which ain't much, is take the motor out and rebuild it. i'm almost positive the valves will be seized in the guides. on top of all that you will need to get the heads reworked to handle the no lead gas, the lead was used as a lubricant and a cooling agent. another words it kept the combustion chamber cooler than what they run today. also you will want to re-seal that motor, the gaskets are so shot from just sitting. then check all other safety related items- brakes anybody?
As stated previously, plus check all the hoses not just the radiator. You want to look at the fuel pump hoses, brake hoses, for dry rot. Tires??? Belts???
Also watch the carb for flooding. Sitting that long the float might be hung up from hanging and it could allow the carb to flood.
And again when you drive it go really easy, those brakes haven't moved in years, ditto the trans and rear, let em get some lube moving around in em as it's all settled to the bottom in that length of time.