ok im new to your forum and it seems that you all know what you are talking about unlike some other forums
i have a 2004 mustang 40th anniversary with a 3.9 that i bought new in 05 as a left over when i was 15

i have a few questions that i could not get exact answeres to on other sites
what is the differance between the 3.9 liter v6 and the 3.8 liter v6
why did ford change the motor in the midle of the year
i have also heard that the blocks are the same but the bore is different so almost all mods except pistons for the 3.8 will work on the 3.9

also one other question my friend has a 04 with a 3.8 and wants to install the prochargers supercharger and the website says the v6 kit is for ford v6 1994 to 2003 why wont it work on a 04 3.8

 

its the same as teh 3.8, just different stroke, there is no difference, not in horesepower or torque, all 99-03 stuff will work on an 04 with the exception of tuners/chips

 

so my 3.9 liter will work with any parts from a 3.8 includeing a supercharger headers exhaust and so on just not chips and programmers

 

yup

 

thank you very much i had searched other forums and no one knew you guys are the best

 

+1

 

you might however get an extra 2ft.lbs on a dyno, and its not really 3.9, its 238 ci wich is like 3.85[8D]

 

so not to be a pain in the *** but the k&n cai for the 04 3.8L will fit my 3.9L? i'd hate to spend a couple hundred and find out it doesn't fit. thanks

 

yes it will fit but i myself wouldnt spens 100's on a cold air intake. get a bomz intake from ebay 40 bucks and its the same 2 horse power