4 GAUGE??? Oh my God! Just kidding, but I'd go to a local auto parts store and order some 2 gauge welding cable. It's pretty cheap and a lot better for running a battery in the trunk/hatch.
Todd, I have the same alternator as you and I let my car idle as low as it will possibly run to get the most lope out of my cam which is around 700RPM
Anyway, my lights never dim. Maybe you need to check some connections? Or maybe you just have a bit more of an under drive than I do.
For what it's worth, you can't always think of under drive pulleys as bieng the "Best bang for the buck" really, because sometimes people have problems and have to upgrade other areas to keep up with the pulleys. But you'll have an even better car if you have to go that route. You'll just be a little poorer than you expected.
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Gunning for 12's!
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