ElementXero wrote
Hey all, running JBL 80.4 for speakers right now, so 320W total

Installing JBL 600.1 on a Kicker 12" L5 in a ~2.0^3 sealed box when the
amp comes on monday.

So thats a 920w rms system in my 1987 Buick Century.

Whattaya think? Dimming lights? Cutting out? Will I be totally fine?

Heh ... seems like a simple question and then everyone starts name-calling
and so on ...
The short anwer is that you will probably be fine, however you won't know
until you are cruising down the highway at night, in the rain, and your
favorite song comes on.
I put three alternators in my '94 Sunbird (all under warranty) before
finally deciding to use a HO (Crappy Tire Premium) alt instead. That was 5
years ago now and it's still working fine (and only a Zapco AG200 ~15 amps
caused that aggravation)