The 3800 Series 2 and 3 are two different versions of the same engine, with some major differences. The most visible difference between them is in the design – while both feature a V6 aluminum block, the 3800 Series 3 has an integrated cylinder head gasket that improves cooling efficiency and reduces emissions. Additionally, the Series 3 features improved performance thanks to its larger bore size (3.890 inches on the intake side) and higher compression ratio (9:1). Finally, improved strength was achieved via better connecting rods and crankshaft designs as well as a higher-flow oil pump.
In terms of power output, there isn't much of a difference between these engines; however, due to their design improvements, they can reach peak torque earlier than previous models for better acceleration off the line. This makes them ideal for vehicles that require quick response times such as police or emergency services cars or sports cars looking for more power from smaller displacement engines. Furthermore, all these improvements allowed GM to reduce fuel consumption by up to 5% when compared to its predecessors and make it even more efficient than before!