The LBZ was relatively short lived, having been available for only two model years for no concise reason other than its replacement, the LMM, was capable of meeting stricter emissions regulations rolling into effect near the time of its retirement.

The all-new 2017 Duramax 6.6L turbo diesel features more torque and horsepower and increased strength cylinder block, heads, crankshaft, connecting rods and pistons. The Duramax features a state-of-the-art oil separator and cold-start system among other features.

Mechanically, the LBZ is nearly identical to the 2006 model year LLY. However, the LBZ features more aggressive engine tuning, yielding a substantial increase in horsepower and torque over its predecessor. The LBZ produced 360 horsepower and 650 lb-ft of torque to the LLY’s 310 horsepower and 605 lb-ft. By mid-model year for 2007, the LBZ was effectively replaced by the emissions compliant, diesel particulate filter equipped LMM.

The LBZ was available mated to either the Allison 1000 six speed automatic or the ZF650 six speed manual transmission. 2007 would mark the last model year that any Duramax engine was available with a manual transmission. The Duramax LBZ was produced from 2006 to 2007 model years, with the LMM replacing it by mid-2007.


Engine: 6.6L Duramax LBZ, 90 degree V8 diesel
Years Produced: 2006 – 2007
VIN Code: D (8th digit of VIN)
Displacement: 403 cubic inches, 6.6 liters
Assembly Site: DMAX engine plant, Moraine, Ohio
Head/Block Material: Aluminum cylinder heads, cast iron engine block
Compression Ratio: 16.8 : 1
Minimum Cylinder Pressure: 300 psi (minimum compression test pressure)
Firing Order: 1-2-7-8-4-5-6-3

Duramax diesel cylinder numbers

Bore: 4.055″ (103 mm)
Stroke: 3.897″ (99 mm)
Aspiration: Turbocharged and intercooled – Garrett GT3788VA variable vane turbocharger (VVT), air-to-air intercooler
Injection: Direct injection, 26,000 psi Bosch high pressure common rail with CP3 injection pump and 7 hole fuel injectors
Valvetrain: OHV (overhead valve), 4 valves per cylinder
Oil Capacity: 10 quarts w/ filter
Engine Weight: Approx. 835 lbs
Idle Speed: ~ 680 rpm
Max Engine Speed: 3,250 rpm (rev limiter)
Emissions Equipment: Diesel oxidation catalyst (DOC) and exhaust gas recirculation (EGR)
Peak Horsepower: 360 hp @ 3,200 rpm
Peak Torque: 650 lb-ft @ 1,600 rpm
Engine Dimensions: Length Width Height
Approx 30″ Approx 30″ Approx 32″