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

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 output at idle RPM and excellent durability in a direct-bolt-in package. 6 phase technology, combined with massive twin rectifier assemblies and 12 diodes makes these alternators totally durable for daily use, while still maintaining great output at low RPM. These alternators will make 180 amps at engine idle speeds with a full 250 amp output at cruising speeds. This unit comes with an OEM diameter pulley, making it perfect for high RPM and racing use. NOTE: This unit may require a rectangle to oval adapter harness if your vehicle was equipped with the CS144 Heavy duty charging option from the factory. (this is not common) Ask a MechMan associate for assistance if you are unsure!