I can't help but laugh at all of the people talking about first gear being useless in a Mach with 4.30 gears and stock tires. It isn't the gears and tires, its the driver. Learn to drive your car and you'll then reap the full reward of what the 4.30 gearset has to offer.
I present a video for your inspection. My 2003 Mach 1 with 4.30s, stock gatorbacks, on the street.
http://www.youtube.com/watch?v=ev29KQzDHXI
All it takes is practice. As I posted 5 years ago in this thread, the 4.30 gear is the single best mod you can make on a Mach 1.