SO let me try to understand what you are saying here. Are you saying that the 2004 Mustang V6 has a 3.9 Liter engine in it? And that it does "NOT" have the 3.8 Liter engine? If this is true, then wouldn't the 3.9 liter engine put out a little more horsepower than the standard 193 horsepower that the 3.8 Liter 2001-2003 V6 Mustangs have? Please enlighten me on this. Thanks.