I have a 04 mach 1 with stock 3.55 gears. I want to install a 4.10 gear. What else do i need to install when i get the new gear. Someone told me i need to get a chip. I that necessary?
You'll need a chip only if your car is an automatic. If a 5-speed manual, then it's unnecessary. I'd recommend a speed cal, since it costs less than a chip.
Speedcal is the easiest, and cheapest way if you have a 5spd. If you have an auto, or you plan on getting a chip burned for a manual car, they can customize it for 4.10's.