Like most car enthusiasts, you'll want to add some modern comforts to your classic or muscle car - and that means an alternator upgrade to power them all. In the early days, there wasn't much need for high-amp alternators because the only accessory they really had to deal with was an additional pair of speakers in the back. But after the 1980s, accessories became more popular as fog lights, sound systems, electrical fans, air suspensions, sophisticated alarms, cameras and more slammed the market. With many older alternators, the 14-16 gauge wiring alone can't handle more than the 45-60 amps factory alternators were putting out -…