3.55 vs. 3.73... Speed difference??

9

94GTPilot

Member

Mar 26, 2006

82

0

6

May 15, 2006

#1

• May 15, 2006

• #1

I was interested in getting a set of gears, and a bit hesitant about going to 3.73 with the price of gas, as I drive on the freeway a lot. Just how much faster in the 1/4 are 3.73s compared to 3.55?

 

OrangeMustangGt

Founding Member

Mar 7, 2002

1,976

0

36

Cape Cod, MA

May 15, 2006

#2

• May 15, 2006

• #2

i went with the 3:73's and my car still got 20 mpg crusing at ~70mph.....with my explorer motor setup.

Go with those......also want to buy mine?

 

9

94GTPilot

Member

Mar 26, 2006

82

0

6

May 15, 2006

#3

• May 15, 2006

• #3

Well I'm not sure when I'm going to do it yet, just in the thinking process at this point..

 

1TallMF

New Member

Apr 17, 2006

955

1

0

Montreal

May 15, 2006

#4

• May 15, 2006

• #4

Mine's about the same - 20-21 MPG on the highway @ 70mph, which is just about 2400 rpms. I get about 18 in the city, and thats driving it pretty hard most of the time HOWEVER: I have read that the speedometer gear is the same for the 3.55's and the 3.73's, and its correct for the 3.55's. That means, with a bit of simple math, that if your speedo says your going 70mph, its more like 66mph (with 3.73's installed). Not a big difference, but something to think about.
Bottom line: a must-have mod for the SOTP feel, for not too much chedda.

 

91LX_5L

Founding Member

May 13, 2002

1,943

0

36

British Columbia

May 15, 2006

#5

• May 15, 2006

• #5

Deff go 373 over 355s I have 355s and wish I went 373 like I did on my last stang. 373 MINIMUM IMO unless your running forced induction.

 

final5-0

Mustang Master

Apr 6, 2003

6,817

12

79

DFW Texas

May 15, 2006

#6

• May 15, 2006

• #6

http://www.allfordmustangs.com/Detailed/608.shtml

Use this to get the facts ... Not opinions or hear say

At legal highway speeds, you're gonna find the difference between the ratios is less that 150 rpm

Now for my opinion

Forget the 355's

373's = More Smiles to the Miles

Grady

 

HGFireHazard

Member

Apr 10, 2005

460

0

17

Michigan

May 16, 2006

#7

• May 16, 2006

• #7

I'm also interested in putting some gears in my car but don't want too steep of a gear for the F/I. My next planned set of mods are an Edelbrock Performer RPM, AFR 165s and a custom cam, would you guys say 373s, 355s, or something else?

 

Black95GTS

Active Member

Jan 8, 2004

1,644

3

38

Marlborough, MA

May 16, 2006

#8

• May 16, 2006

• #8

HGFireHazard said:

I'm also interested in putting some gears in my car but don't want too steep of a gear for the F/I. My next planned set of mods are an Edelbrock Performer RPM, AFR 165s and a custom cam, would you guys say 373s, 355s, or something else?

Click to expand...

I would say 4.10s. Do not fear more gear. Like Grady said, more smiles to the miles.

I bet if you ask your cam grinder, he's going to suggest 4.10s for that combo.

Adam

 

94-302-vert

Active Member

Aug 16, 2004

1,947

2

36

NE CT

May 16, 2006

#9

• May 16, 2006

• #9

go 3:73... I went 2:73 to 3:73 and didn't lose a drop of milage and have a lot more fun... and I drive 45 miles each way to work, 20 miles of that is on the highway at 75-80 mph...

 

VooDooChild

Founding Member

Nov 29, 2001

201

0

0

MidTennessee

May 16, 2006

#10

• May 16, 2006

• #10

I have read that the speedometer gear is the same for the 3.55's and the 3.73's, and its correct for the 3.55's.

Click to expand...

I would not do the speedometer gear swap. Spend the money on a SpeedCal and do it right. It will also allow you to adjust for tire size and ring an pinion. I went from 3.08 to 3.73 and used the speedcal and it was dead on when I checked it with my GPS.

 

gustang818

New Member

Mar 10, 2006

48

0

0

May 16, 2006

#11

• May 16, 2006

• #11

I wish I would have gone with 4.10s instead of 3.73s.

 

9

94GTPilot

Member

Mar 26, 2006

82

0

6

May 16, 2006

#12

• May 16, 2006

• #12

1TallMF: 18 in the city?!?! And you push it hard?!?! Wow, I get a little more than 200 miles/tank, and that's driving it pretty easy... Do you know what can kill milage like that? My motor is stock, 170,000 miles, flowmaster exhaust, o/r h pipe..

final5-0: 150 rpm, huh? That's almost nothing.. I have a whine coming from what I think is the rear end, and when I do my entire clutch system taken care of over the weekend, I am going to have a buddy check out the rear end with me.. I have a feeling I may have to replace the gears? and why buy stock when you can upgrade?? Don't you hate it when a stock part goes by the wayside?? haha, upgrade time!!

 

94venom5.0

New Member

May 15, 2006

6

0

0

Griffin, Georgia

May 16, 2006

#13

• May 16, 2006

• #13

another thing to think about, a lot of guys will tell you no but, i put the pro 5.0 3:90's in my 94 and i love em..no noise at all and great SOTP feeling and def. do the SPEEDCAL

 

1TallMF

New Member

Apr 17, 2006

955

1

0

Montreal

May 16, 2006

#14

• May 16, 2006

• #14

VooDooChild said:

I would not do the speedometer gear swap. Spend the money on a SpeedCal and do it right.

Click to expand...

The previous owner put those gears in about 2 years ago, so I don't know what was done with the speedometer. Had I done it, I would most likely do the speedcal. All I know is my speed appears to be correct