I was wondering how big of a difference 3.73 gears would make on my '05 GT?

 

Is it an auto or manual?

 

very lilttle

4.10 auto 4.30 5 speed unless you trap higher then 115 mph

 

Probably not a whole lot. Mine had 3.31s stock and I changed to 3.73s. It made some difference, but I wish I had gone to either 3.90s or 4.10s. If your stock gears are 3.55s then you won't notice a whole lot at all.

 

I have a 07 with 5 speed manual. I upgraded from the stock 3.31's to 3.73's. I find these gears to be a nice gear for how I drive the car. I can zip around town, yet the rev's are not sky high when cruising down the freeway. For my style of driving I think the 4.10 and especially the 4.30's would be too much.

 

I hear a lot of manual guys talking about how big of a difference the 4.10s make, after upgrading from 3.55 to 4.10 (a difference of 0.55). Wouldn't the auto guys upgrading from 3.31 to 3.73 (a difference of 0.42) experience a similar improvement (although not quite as much based on the numbers), or does it not work that way?

 

Quite a few posts on this subject.check my post on 4.6 specific.

 

No, because the gear ratios are different for the automatic.

http://www.allfordmustangs.com/artma...OVERVIEW.shtml

Enter the data into an RPM to MPH calculator and you'll find out that RPM with 3.73:1 in an auto approximately equals the RPM with 4.10:1 in a manual. Putting 3.73:1 in a manual would be a slightly higher RPM than putting 3.55:1 in an automatic.

That's why the majority recommend 3.73:1 for the automatic and 4.10:1 for the manual. Some say more, of course. There have been many threads covering the subject.

 

1+