dave86

I've been wanting to get 3:73s, but since my car is auto, maybe i should get 3:90s. The problem is that I can't find any made by Ford Racing. I found some made by motive, but I probably shouldn't go with them right? I don't really want 4:10s, so if I can't find any good 3:90s, then I guess it's gonna be 3:73. What do you all think?

02StanGT

Ford doesn't make em. I believe you are right, only Motive makes em. Several of the guys are running Motive gears and they have no problems with em.

4600cc

What's the top speed with 3:73, 3:90, and 4:10? Provided that you have stock tires and 5-speed?



AL

The Great Cornholio

If you really want 3.90s get the Motive gears, they should be fine. Why do you really not want 4.10s, especially with an automatic transmission?

dave86

More than half of my driving is highway driving. I have to get on the highway to go to work every day. My mpg should be about 18 on the highway now. Would it go below 15mpg with 4:10s? I also don't wanna top out real low. Do you think I would top out at like 120 with 4:10 or would it be even lower? I've never had a chance to top out my car, but it's been at 140mph before. I know 3:90s would be bad for my fuel economy and top end too, but better than 4:10s. I figured having 3:90s would make up for having an auto, guess not?

The Great Cornholio

I am getting about 20 mpg and have a daily commute to/from work of 50+ miles, mostly on the highway. I personally would use 4.10s with an automatic, but 3.90s are a good split between them and 3.73s.

dave86

How high does your rpm go at around 70mph?

BLOWN05GT

I put motive 3:90s in my supercharged 05 GT and they are working great...top end speed is still off the dial.

The Great Cornholio

At 70mph I don't know, but it's not at 3,000 rpm until 90 mph. Different transmission though.

Dan04COBRA

https://mustangforums.com/m_600073/tm.htm