MAX HORSEPOWER: 460-500 HP TUNING: EFI LIVE
Thanks to its ability to access and alter virtually every parameter in the ECM, EFI Live was nothing short of revolutionary when it debuted in the Duramax segment. Once aftermarket calibrators had mastered the software, 6.6L-powered GMS were more powerful, efficient and driveable than they’d ever been. More than a decade later, it’s still the tuning method of choice for truck pullers, drag racers and daily drivers alike. Taking advantage of all that EFI Live has to offer, many tuners can push an LB7 to the 500hp mark, especially in a ZF-6 truck with a clutch upgrade. As for the stock Allison, it’s on thin ice at this power level, which is why most tuners draw the line between 425 and 450 hp.