I have a 2013 GT, Manual, with 3.31's. All the mustang's I test drove before the one I currently own had 3.73's and felt a lot more powerful than this one. I have been looking to get 3.73's installed, but hear a lot of people complaining about how 1st gear is too short and bad fuel economy. Currently 3.55's are on sale this month from http://www.americanmuscle.com/yukon-355-1113gt.html for $130. Does anyone here have 3.55's? What do you guys think?

 

I don't understand people who say that 1st is "short" with 3.73s. There is another good thread here which talks about this issue extensively. It also has a good spreadsheet which shows you speed in each gear in 100rpm intervals.

But here is a snapshot of top 1st gear speed at 7k:
3.73 - 42mph
3.55 - 44mph
3.31 - 47mph

I don't think 1st is short in any of these versions.

 

I had the same question when I got my GT. Was either 3.55 or 3.73. I went with the 3.73, no regrets. 1st is fine. It's also my DD. I suppose you could even go with 4.10s if it wasn't a DD.

 

Get the 3.73s you can easily start in 2nd gear in traffic and 1st gear if you want to take off hard.

 

Went with 3:73, so far so good! But this isn't my daily driver.

 

I bought my car with 373 and would love to have 355's I hate first gear and my mpg blows

 

Changing from 3.31 to 3.55 is not worth it, hardly any change at all.

I have 3.73's and they are just fine, use first gear all the time so don't know why anyone would say it's useless. Now, the V6 guys have a different story with 3.73's since first gear in their transmission is so much lower than in a GT.

As to drag racing with the 3.73's, they are right on the edge at the strip on stock tires. I end up riding the rev limiter through the traps in mine or else have to shift to 5th gear losing some momentum. This will be fixed when I get my drag radials as they will be 1" taller than the stock tires.

The only other thing to consider is tuning, if you want the speedometer to read right you will have to either get a tune or have the pcm flashed at the dealer for the gear change.

 

If you plan on ever doing FI, don't get 373's.

I have 410's and 480whp in my 5 speed 2007 and with 315's traction is still a problem. Since the 5.0 makes substantially more torque, I wouldn't go any shorter than 355 with FI on a 5.0 making 550-600whp

 

oh wow, I never really thought of that...you make a good point. But hell, I probably won't be doing FI until the kits come down to fox body prices...so I could probably just put the 3.31's back in it. Lol

 

Maybe it’s just me but I always felt the opposite, taller gears (3.73:1) = easier to move the car, longer legs (3.31:1) = easier to spin the wheels than move the car. Got me thinking it could depend on how good the traction is on the individual car?

 

I have been thinking of going the other way. I use 2nd 90% of the time to pull off from stationary. I use my car daily and drives have been getting longer so I will reap some benifit of 3.31's. However I do like the 3.71's for that quick get away.

 

Ok, I actually owned all 3 gears. I'm a car nut which is an understatement to say the least. I've owned an 11' 5.0 w/3.31, another 11' 5.0 w/3.73 and now a 13' 5.0 w/3.55's. I personally like the 3.55's the best. The 3.31 felt a little slower on take off which made it feel not quite like what I thought a muscle car would. The 3.73 made 1st gear un-usable at times to say the least; they were fun no doubt when there was room to run, but for DD they were annoying. The 3.55 seem to be the best of both worlds, they keep the RPM's low on the highway, but are still usable and powerful down low. As far as mileage between all 3, the 3.31 got the best and 3.73 was the worst, but only by about 2mpg. As for the 3.55, I really couldn't say because I live on Fort Carson and the max speed limit is 30mph which makes my mpg horrible. Hope this helps!

 

Thank you 1badmax! You have a great opinion since you've actually driven a mustang with all 3 gear sets. I may waste a salesman's time this weekend test driving a 5.0 with 3.73's, just to remind me of the feel. I feel bad doing that, but its a necessary evil.

 

I had 3.73's on the order sheet and changed to 3.55's at the very last minute. I plan on going e-force soon and with having traction problems already I'm glad I have the 3.55's.

 

I have 3.73s on my ROUSHcharged car.....really wish I had 3.55s!
Even w/o the SC I woudl spin gears in 1st on a hard launch....should have known!

 

First gear with 3.73 is useless in the sense that unless you want to wind up to 6k rpm you need to shift to early. I take off in 2nd 90% of the time. I do love 1st for hard launches and track use.

 

Question though, have you gotten a tune for your car? I tuned my Stang with the 3.31 and it picked up a little down low especially with Bama's Race tune. Just a thought!

 

I have 3.73's and don't find first useless or get unusually low milage (26 mpg hwy, 17 mp when I'm enjoying myself around town). I did notice a big difference coming from the 3.31 on the cars I test drove. If you're not planing to go FI, I'd go 3.73 - 3.55 is not enough o a difference to warrant the cost of the upgrade.

 

I have had both 3.73 and 3.55 and I prefer 3.55. Best all around gear for a high power street car.

 

All you guys who are blowing the tires off need to invest into better tires and suspension....