Updated 5.4 with tune and WOW
Funny you say that, I wondered the same thing. I asked around for a long time before I began this project and all said that as long as I had the tow package gears (373) that I would be fine. I know that a larger gear ratio will be better but a ton a people are running the same set up. 4.56, do you really need to go that high? Is it that much better than the 4.10's? I have a 2x4 screw and it will never see off road. Just for looks, I know its a disgrace but its what I have.
I called the dealer and had them run the vin# to give me the gear ratio and its 3.73. The tuner is set to 3.55 from SCT so I switched it to 3.73 to match what I have. What year and engine size do you have. Mine is 08 5.4l
Never mind I see its an 05 which I am guessing is a 4.6l?
Never mind I see its an 05 which I am guessing is a 4.6l?
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Jim
Jim
Where in CA are you located? If you are in Socal or the valley and are only on flat land, the 3.73s will be sufficient for the 35s. If you are in the mountains of NorCal or go to Tahoe at all, you will really want taller gears as the tranny struggles uphill with the larger tires.
I never have kept the stock gears in my mustangs so I am sure I will end up changing these also.
Will 4.10's be sufficent? I even just saw a 4.30 which may be a happy medium. I am worried about the 4.56's bc I do 90% of my driving on the highway at 75-80mph.
Will 4.10's be sufficent? I even just saw a 4.30 which may be a happy medium. I am worried about the 4.56's bc I do 90% of my driving on the highway at 75-80mph.
Last edited by rrozell; Mar 14, 2011 at 05:58 PM.
Thanks, why didnt I think about that?!?
But if I am paying for a custom tune why not get it to include 91 octane to get the most power out of the motor. Bigger bang = more HP
The change from 3.73 to 4.10 wont justify the cost. Do 4.56s if you decide to drop the cash. I would try the 3.73s for a while though, i think you will be okay on flat ground as long as you have custom tuning.






