MAX HORSEPOWER: 460-490 HP TUNING: EFI LIVE
Although it comes with a stronger Allison 1000 behind it, the LML Duramax isn’t quite capable of matching the 500hp number that the tuned ’01-10 trucks can. The CP4.2 injection pump, which flows approximately 20 percent less fuel than the previously used CP3, is to blame for this. For most owners the difference in horsepower is marginal as well as hardly noticeable. For those who are worried about their LML’S horsepower deficiency when compared to the earlier trucks, CP3 conversion kits are available in the aftermarket.