You may get more responses in the “Computer Chips” forum down below. Superchips has a chip for the 4.2 that adds somewhere around 25hp or so and 30 or so ftlbs of torque. You will get better information there. Mike is the Superchips rep in that forum and you can either ask him questions on that forum or use the information below to contact him.
Hope that helps…
Troyer Performance/Performance Products, Inc.
Truck & SUV Performance Specialists
Web Site: BUY YOUR SUPERCHIPS HERE: TroyerPerformance.com
National F-150 Online Rally Event Organizer