Twisted

I had planned on getting a set of 3.55s put in this week. I chose 3.55s because the owner of the shop who is doing the work says that the speedo can only be calibrated correctly with 3.55s or smaller (numerically). Although he seems extremely knowledgeable about 5.0s in particular, I was under the impression that you can get the correct speedo gear for any size gears, including 3.73s. Can anyone confirm or refute what the shop owner has told me? Thanks.

Stevens91gt

yes..u can get them for the higher gears..at least thats what ive heard

Twisted

That's what I thought. I've done a search on this site, and it seems that you can calibrate the speedo correctly with 3.73s. I just wonder why the owner said that considering all the 5.0s he's worked on.

Stevens91gt

ya cuz i jus looked on a few websites and u can change it..
so idk maybe u should show him the sites? or sumthin

Twisted

Good idea. Thanks Steven.

93Mustang5.0

Well I have 3.73's and im in desperate need of a new speedo gear because when im going 70 on the interstate im really going 63. My friend clocked this saturday night. I know that the 21 tooth is for the 3.55 so im guessing that I would need a 24 tooth? In my 50resto book for 79-93 stangs, they only carry up to a 3.55 speed gear.... So does anyone know where I could find a gear for 3.73's?

biglg

You can get the gear from someone online I am sure. Just look around. I got mine from my local Ford shop. Ttransmission shops can get them, if they dont have them on hand. Here is the information I found online about the different year mustangs, and the speedo gear needed for different rearend gears. I hope this helps you guys out.

Speedometer Gear Help Guide

Ring & Pinion Speedo Gear Part Number

1983-89 Mustang Manual 5-Speed
3.08 18 Tooth LRS-17271H
3.27 19 Tooth LRS-17271A
3.55 20 Tooth LRS-17271B
3.73 21 Tooth LRS-17271C
4.10 23 Tooth LRS-17271D

1990-93 Mustang Manual 5-Speed
3.08 20 Tooth LRS-17271B
3.27 21 Tooth LRS-17271C
3.55 23 Tooth LRS-17271D

1984-89 Mustang Automatic AOD
3.27 19 Tooth LRS-17271E
3.55 20 Tooth LRS-17271F
3.73 21 Tooth LRS-17271G
4.10 23 Tooth LRS-17271J

1990-93 Mustang Automatic AOD
2.73 19 Tooth LRS-17271E
3.08 20 Tooth LRS-17271F
3.27 21 Tooth LRS-17271G
3.55 23 Tooth LRS-17271J

1996-98 Mustang Cobra Manual 5-Speed
3.27 19 Tooth LRS-17271A
3.55 20 Tooth LRS-17271B
3.73 21 Tooth LRS-17271C
4.10 23 Tooth LRS-17271D

1994-98 Mustang Manual 5-Speed
Except 1996-98 Cobra
3.08 20 Tooth LRS-17271B
3.27 21 Tooth LRS-17271C
3.55 23 Tooth LRS-17271D

1994-98 Mustang Automatic AOD
2.73 19 Tooth LRS-17271E
3.08 20 Tooth LRS-17271F
3.27 21 Tooth LRS-17271G
3.55 23 Tooth LRS-17271J

86HOGT

3.73s in a 84-89 T-5 is a red 21 tooth gear.

performance1985

I also had to replace my speedo gear in my 87 GT Conv. unfortunately with an automatic though. I put in 3.73 gears and had to switch out to a 23- tooth speedo gear to bring the speedo back within range. Each tooth equals about 5 miles an hour, just fyi.

marx91

with 3.73's the speedo gear alone isnt going to do it
the drive gear in the trans has to be changed too