Power woes

[RoadWarrior]

For the longest time I've been running low on power in my car. According to my voltage gauge my car gets sufficent power until I begin turning on accessories. With all my accessories going the volts start dipping to the 12-12.5V side of the gauge. I figured it might be because of the extra drains I've put on.

I added a Holley Blue pump, an electric fan, a decent stereo, MSD ignition, and I - think - thats about it. But when all is said and done on a cold day it starts to run low on volts. I know '82's didnt have big alternators, but I did get a brand new replacement alt but I'm wondering if the 65amps is good enough.

Should I opt for a 100 amp one...even higher?

Thanks for any suggestions you can give.