So, my 86 has had this issue for quite a while. I'm unsure if it's because everything is manually run on the car now instead of being hooked to a computer. The car has a charging issue. In the past year, i've replaced 3 alternators. I had i think a 78 in it, which was low. I have a 94 in it now, but the ac compressor drops my gauge down to around 11 from 14. The engine no longer kicks up the idle when i run more things..and the car idles low around 500rpms. I know the gasket around the carb was leaking..so i'm sure it's not helping. Anyone have any suggestions?

Car has a 350 Chevy crate. Not sure if the sound system might be hurting it. I have 2 amps, and a sub box in the back. The lights dim every time the bass hits