All 3x00 engines are a 3.xL engine, but not all #.xL are 3X00. Drive any 3.1 or 3.4 car, and then drive a car with a 3400 in it. They are tuned differently and the 3x00 series have more power (on all models i believe). The 3800 is GM'* premier car V6, there is the 4.3 in trucks but that was replaced by the new Vortec I-6 which is very balsy at 275 HP and 285 Lb/ft i believe.... Maybe a lil less.