Type: 4.4L DOHC 32 valve 90()() V-8
Manufactured: Performance Build Center, Wixom, Mich.
Displacement: 4371 cc (267 ci) Bore x Stroke: 91 mm x 84 mm
Compression Ratio: 9.0:1
Valve Configuration: Dual overhead cam (4 valves per cylinder)
Valve Lifters: Roller follower with hydraulic lash adjusters
Valve Head Diameter: Intake: 36 mm
Exhaust: 29 mm
Firing Order: 1-2-7-3-4-5-6-8
Engine As Shipped Weight: 229.7 kg (506.4 lbs.)
Engine Control Module: Delphi E67 ECM, 40 MHz control unit, 2 megabytes external flash memory and 128 kilobytes external SRAM
Additional Features: Piston spray cooling Friction washers at front of crankshaft Platinum tip spark plugs
Fuel System: Sequential Fuel Injection Returnless system
Injector flow rate: 40 g/s Premium required, 91 minimum octane
Horsepower: 440 (328 kW)@ 6400 rpm (estimate)
Torque (lb-ft): 430 (583 Nm) @ 3600 rpm (estimate) 90 percent of peak torque available between 2200 and 6000 rpm
Fuel Shutoff: 6700 rpm
Emissions Control: BIN8/EURO 4 compliant Close-coupled catalytic converters EGR and AIR not required
Oil: Synthetic 5W-30 9 qts. with filter
Block: Upper - sand-cast 319 T7 aluminum, Lower - die-cast aluminum
Bore spacing: 102 mm
Cylinder Head: 319 T7 semi permanent mold cast aluminum alloy with polished exhaust ports
Supercharger / Intake: GM patented integral design. GM specific helical Roots rotor set, cast aluminum case 2.0L (122 ci) displacement 2.1:1 pulley ratio, Four laminova style intercoolers Modulated bypass
Crankshaft: Forged steel with rolled fillets
Camshafts: Cast nodular iron
Cam Phasers:
Intake: Initial timing 133 degrees ATDC with 40 degrees advance authority
Exhaust: Initial timing 117 degrees BTDC with 50 degrees retard authority
Valve Lift: Intake: 10.5mm (.413 inch)
Exhaust: 10.0mm (.394 inch)
Duration @ .050"
Intake: 202 degrees
Exhaust: 214 degrees
Pistons: Cast aluminum, polymer coated, anodized top land 5.4mm, full floating 24mm pin
Connecting Rods: Powder Metal with heat treatment
Length: 151 mm
Exhaust Manifold: Cast nodular iron Accessory Drive Three belts
Rear: Alternator
Middle: AC, PS and water pump
Front: SC

The supercharger is undeniably the key feature of the LC3, and as with any forced induction engine the objective of the system is to drive airflow through the system, inducting a greater charge with each cycle. The roots-type blower installed on this Supercharged Northstar engine takes a flowpath very different than that which is the norm in traditional GMC blowers familiar to hot rodders. The flow path as illustrated here is from the rear of the case, moving the air forward, upward, and to the centerline of the rotor housing. In the development process, the attention to airflow was not limited to just the supercharger. Here are some of the highlights.

The use of low restriction mass airflow sensors and air cleaners to reduce restriction and enhance flow.Induction tubes, which split and run along the upper sides of the engine before rejoining at the rear-mounted throttle body, that were developed with CFD (computational fluid dynamics) to deliver the required high airflow with low restriction.

Induction silencers, integral to the new induction tubes, co-developed by GM Powertrain and WocoTM to markedly reduce induction noise without reducing airflow.

High-flow Northstar V-8 cylinder head ports that are further refined with ExtrudehoneTM abrasive surface treatment. This patented process polishes the ports to improve flow.

Specific exhaust system, tuned for low backpressure, improves power for the STS-V. Larger diameter outlets on the close-mounted catalytic converters are used in the STS-V exhaust system.