I found some info on the 2004 the web site is called History of Mustang Performance 94 - 02
This is the article
Drawing from Mustang & Fords magazine
The Mustang moves to a new platform, the S197, a shortened, modified version of the rear-drive platform with independent suspension that's shared with the new T-Bird and the Lincoln LS. Horsepower is expected to increase to around 285 for the GT and 350 for the Cobra with a 5.0L version of the DOHC .