Wrinkle Black HD High Output Alternator 2001-2007 GM 6.6L Duramax XD355 XDPIncrease the output of the charging system in your 2001 2007 GM 6. 6L Duramax with the XDP Wrinkle Black HD High Output Alternator XD355. The Duramax engine is a known powerhouse that is easy to modify, but the charging system is often forgotten about until there is an issue. The demands of popular add on accessories like aftermarket horn kits, on board air compressors, off road lights, plows, stereo equipment, and other electronics can quickly exceed