Alt(specific question)

you can get a 3g alt for a little more money at most parts stores. i have a 3g 200 amp alt and its awesome.

you can get them in 130 amp also. its worth getting a nice alt once incase you ever get a stereo, electric fan, or anything that takes more juice so you dont need to buy another.

Upgrade your alternator, and the alternator wiring.

Headlights and the AC fan alone are enough to really tax your stock alternator. At low engine RPMs, you can be draining the battery. Now you add an electric cooling fan and fog lights, and you'll really be short on amps.

Don't forget to upgrade the alternator wiring too. The increased current capacity needs larger wires, or you'd be asking for an electrical fire.

PA-Performance also has 3g alternators in a 2g case. www.pa-performance.com
That's what I would recommend. They also offer that same alternator for use on 86 and oler cars that are setup for the two wire regulator harness (which is what you have). All it really means is that you won't have to rig up a stator wire. Makes for a nice clean installation. I believe the two available versions (for the 3g in the 2g case) is 130 amp and 150 amp. Either one will do. You won't have to cut or modify any brackets to install it. It's a direct replacement. Be sure that you get either the standard or premium wire upgrade (you'll need the long one). If you don't plan on running any stereo equipment then the standard is all you need.

a parts store can likely test the charging system for you (or you can get some numbers yourself). carbed set ups dont absolutely necessarily need to get the upgrade, but like everyone said, if getting a new alt, why not. room to grow.

good luck.

Here's websites with pictures of the 3G installation...

See http://www.geocities.com/smithmonte/Auto/3G_130A_Alternator_Upgrade.htm - all the tech data you could ever want to know
OR
http://www.mustangcentral.net/tech/alternator.html - excellent pictures of installation

Use these sites for information on the right way to do the wiring. Some people will tell you that you can skip the wiring upgrade, but it will catch up with you sooner or later. A fire in the wiring harness is ugly and expensive.

Under no circumstances connect the two 10 gauge black/white wires to the 3G alternator. If the fuse blows in the 4 gauge wire, the two 10 gauge wires will be overloaded to the point of catching fire and burning up the wiring harness.

Electric fan = 3G alternator if you want long life & reliability from your car.

Figure this:
Ignition system & computer = 12 amps
Fuel pump = 12 amps
Exterior lights = 15 amps
Fan (heater or A/C) = 15 amps (can run between 5-25 amps depending on setting)
Radio & instruments = 10 amps
Wipers = 10 amps

That's grand total of 74 amps from a 65 amp alternator. Talk about overdrawn at the bank!