underdrive pulleys, how do you like/hate them?

I got March pulleys w/ stock alternator and h2o pump......and I have the same problem, with my lights dimming at idle, as jimberg. I'll upgrade to a 130 amper when this one goes

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'90 LX 5.0;12K original miles;FMS 3.55 gears; March pulleys;Edelbrock Performer Heads;BBK 1 5/8" equal length shorties;MSD 6AL ignition w/ blaster 2 coil;FMS E303 cam;Pro-M 75mm MAF;BBK 70mm TB; Eibach drag-launch spring kit;Southside weld-on subs;9" K&N cone filter charger;Hurst shifter;Cervini 3" turbo hood;A/C delete;gutted cats;2 chamber Flomasters;Corbeau racing seats;FMS 30# injectors;JMS custom chip;Holley 190lb fp;TFS track heat intake (12.299 @ 113mph w/ a 1.78 60')
....soon to be b