250 Amp High Output Alternator - 2001-2007 6.6L Duramax LB7/LLY/LBZ & 1996-2004 GM Gas - Machined Billet

250 Amp High Output Alternator for 2001-2007 6.6L Duramax LB7/LLY/LBZ

Fits the 6.6L Duramax in 2001-2007 Chevrolet and GMC HD trucks (LB7, LLY and LBZ) and the 1996-2004 GM gas trucks that share the same case and mount. This is a direct bolt-in upgrade over the factory unit — same mount, same pulley position, no bracket modification.

Diesel engines spend most of their working life at low RPM, and that is exactly where a stock alternator runs out of headroom. This unit holds 200+ amps at engine idle and delivers a full 250+ amps at cruising speed, hot rated — enough for a lift pump, auxiliary lighting, a winch, a plow, a welder or a competition-grade stereo without watching your voltage sag at every stoplight.

Engine codes covered: LB7, LLY, LBZ

Vehicles: Silverado Sierra 2500HD 3500HD, Suburban, Tahoe, Escalade

Manufacturer specifications and full fitment

The Elite series 250 amp alternator offers great amperage output and durability at a great price. 6 phase technology, combined with massive twin rectifier assemblies and 12 huge diodes make these alternators totally durable for daily use. These impressive alternators produce 180+ at engine idle RPM and 250+ amps at cruising speeds HOT RATED. If you're building a show AND GO vehicle, this alternator is high RPM friendly while still offering plenty of output for a 2,000-3,000 watt audio system(more with extra batteries)! This alternator is very universal which will fit your standard 96-04 GM Truck/SUV applications but can also be used in motor swaps or as secondary alternator setups as it only requires 1 wire to a 12v switched source from the vehicle to turn on and off. Simple, solid and RELIABLE.

These Large Case billet units are the same housings we use in our iconic 370 and 400 amperage offerings. But with the larger 2.2" 6 rib pulley(other sizes can be substituted upon request/application) it is much more at home in racing applications that require excellent charging at vehicle idle speeds while offering high rpm / above 5000 vehicle RPM capabilities while complimenting a show vehicle engine bay. If you are unsure if this application will meet your needs, please call us to discuss. Please have ready your vehicle's crank pulley diameter, vehicle idle RPM's and vehicle's MAX RPM's known for most precise results.

Fitment Guide: