. Vortec 4200  The LL8 (or Vortec 4200), is a straight-6 truck engine. It was the first Atlas engine, and was designed for GM's new SUV line. It displaces 4.2 L When introduced, this engine's power was 270 hp (205 kW) at 6000 rpm and torque was 275 ft·lbf (373 N·m) at 3600 RPM. 2003 saw a slight bump in power to 275 hp (205 kW), while torque was unchanged. For 2006, power was increased to 291 hp (217 kW) at 6000 rpm and torque to 277 ft·lbf (376 N·m) at 4800 rpm with the addition of a MAF and a complete internal redesign of the engine. The Atlas LL8 was on the Ward's 10 Best Engines list for 2002 through 2005. Engine redline is 6300 rpm. LL8 Applications: · 2002-2009 · GMC Envoy, Envoy XL, and Envoy XUV  · 2002-2009 · Chevrolet TrailBlazer and TrailBlazer EXT  · 2002-2004 · Oldsmobile Bravada  · 2004-2007 · Buick Rainier  · 2003-2008 · Isuzu Ascender  · 2005-2009 · Saab 9-7X With the closing of the Moraine, OH plant and the termination of the GMT-360 platform (Chevrolet TrailBlazer, GMC Envoy, etc) the Atlas LL8 (Vortec 4200) has also been terminated. The smaller I4 and I5 variants are still produced. Vortec 4200 Displacement 4160 cc (254 cu in) Cylinder bore 93 mm (3.7 in) Piston stroke 102 mm (4.0 in) Power output 291 hp (217 kW) at 6000 RPM   (2006 and up) Torque output 277 lb·ft (376 N·m) at 4800 RPM (2006 and up) In 2002 when the engine was introduced, GM made a tech paper, click on the link below to download a copy  The paper describes some of the features and advanced engineering and processes that have gone into the development of this engine.  These include the advanced electronics and Variable Valve Timing (VVT). The engine is a double overhead cam configuration with 4 valves per cylinder.  The aluminum cylinder head is a cross flow Design with the intake manifold on the drivers side and the exhaust manifold on the passenger side.  The water pump housing is integrated into the aluminum cylinder block,  The oil pump is a gerotor type and is installed into the timing chain cover and driven directly from the crankshaft.  The main bearing caps are held on with 2 bolts each.  The cylinder head has 4 bolts per cylinder (see below).  The two cams are driven by a timing chain on the front of the engine.  The exhaust cam which is located on the passenger side of the cylinder head has a special sprocket that enables the cam timing to be advanced or retarded.  The timing of the intake cam is fixed. The VVT is controlled by a solenoid valve that meters oil into the cam actuator.  A sensor is triggered by a wheel on the front of the cam and the engine control computer compares the cam sensor the the crankshaft sensor signal, depending on the cam angle required, the engine control computer will command the solenoid to advance or retard the cam.   The angle desired will be determined by engine rpm and load.  As you can see from the illustrations above and below, the starter motor is installed high on the drivers side.  This may cause problems with engine swaps because the traditional location for a starter motor is low on the passenger side. The engine has a bellhousing bolt pattern that is unique to the Atlas engine family.  All of the vehicles the engine was installed in used the 4L60E automatic transmission.  This causes some problems when it is desired to install the engine into a vehicle with an standard transmission.  An aftermarket flywheel is available and the standard transmission bellhousing  from the Colorado and Canyon pickups will bolt up to this engine.  Please see the swap section for more information. Vortec 4200 Engine block Engine weight (complete) 470 lbs The Block deck height is         9.160 Standard chamber volume      68cc Intake runner volume 190cc Exhaust Runner volume 93cc Stock valve lift .370”