Hey everyone. Ok, so I got a new Mustang...2007 GT...and I am looking to make it go faster, but I want to keep it naturally-aspirated so no turbos or superchargers. I have plans for modifying the engine but then was also looking into the diff and had some questions about that. First off, I have seen that a lot of people have opted for the 4.10 ring & pinion setup for a more snappy response off the line...but what about a 4.56 ratio? I know the higher the ratio, the quicker it is but at the loss of fuel consumption so I guess I am wondering if anyone has made this conversion and if so, how much worse was it? I am looking more for sprinting speed over top-end so not worried about the obvious loss there with a higher gear ratio...just wondering if it is worth settling for the 4.10 with a more balanced speed/fuel mileage ratio or going more extreme with the 4.56 gear set

Also, since I will have the diff apart for this mod, I will be swapping out the stock diff with a new Ford Performance 31-spline Traction-Lok one as well as new 31-spline axels. My question here is...is there anything else I should be changing or swapping while doing this? I saw someone mention something about needing a new ABS tone ring in a parts review on AM.com so is this necessary as well...and if so, is there one or two rings?

 

Assuming you have a standard transmission the normal performance gear ratio is 3.73 so stepping up to a 4.10 is a big step in of it's own and probably as far as I would go unless some sort of bracket drag racing is in your future. A 4.56 would pretty much eliminate the need for first gear under normal driving conditions. We're talking changing gears before you clear the intersection almost. Freeway speeds would guzzle the gas, probably as much as 1500 to 2000 RPM or more depending on tire size as well.

 

I appreciate the help on this. Also, I did some research and found out that I need only one ABS ring.