Mustang Bullitt Forum banner

3.73 Gears???

583 Views 18 Replies 8 Participants Last post by  Bullittbabyc1796
OK so I bought my Bullitt 3 years ago with mods. Its got the basics Intake, full exhaust, timing adjuster, 3.73 gears..... and a box full of what I was told OEM parts now come to find out the 3.73 gears are in that box brand new never used. stupid me lol, I should of looked. Now my question is should I get them installed would it make a big difference... let me know what you guys and girls think. thanks
1 - 19 of 19 Posts
Yes,the gears will make a nice difference. Put them in!!
Might as well do the ger swap if you already have them sitting there!
YES put them in. It really wakes the car up.
As soon as you read this, I want you to grab your keys, get in your Bullitt and go have the 3.73s put it. Trust me.
Gear are SOOOOOOOOOOOOOOOOOOOO worth it!
wow thanks for the fast replys, Im going to get on top of my gears asap... I just can't believe the previous owner didn't do it. thanks again.
Yall make me want to go out and buy some 3.73's....:-B

See less See more
Bullittbabyc1796 said:
OK so I bought my Bullitt 3 years ago with mods. Its got the basics Intake, full exhaust, timing adjuster, 3.73 gears..... and a box full of what I was told OEM parts now come to find out the 3.73 gears are in that box brand new never used. stupid me lol, I should of looked. Now my question is should I get them installed would it make a big difference... let me know what you guys and girls think. thanks
You will like the 3.73 gears! You should also plan to get the SCT programmer to recalibrate your speedometer. A new tune may help maximize your existing mods. If you don't drive a lot of miles on the car I would suggest splurging for 3.90 gears. My gas mileage dropped from 25.5 avg to 22.5 avg with the 3.73 gears. Even so, I would go with 3.90s if I were doing it again. Torque multiplication is SWEET:smile:

You will not regret the gear upgrade!
well, Im going to just go for the 3.73 since I don't have to buy them, and I thought they were in there aready. I also have this red thing with gears like splinds, package says gear speedometer"part# c40z-17271-a" I think thats going to fix the speedometer issue
Bullittbabyc1796 said:
well, Im going to just go for the 3.73 since I don't have to buy them, and I thought they were in there aready. I also have this red thing with gears like splinds, package says gear speedometer"part# c40z-17271-a" I think thats going to fix the speedometer issue
That will not work on our cars. In order to recalibrate the speedo you will need either a Speedcal or a tuner.
ok so how off will the speedo be 5mph or so
Yeah, something like that. It won't be so bad that you have no idea how fast you are going. But to avoid talking to you friendly local police... you should get it fixed as soon as possible.

When I did a gear swap in my old '89 5.0 from 2.73 to 3.73 it was right about 10 mph off at 70. So 3.27 to 3.73 should be around 5 mph difference.

I had the Bullitt recalibrated right after the 3.73 swap, so I don't know what the differance was. I drove that 5.0 for years with the speedo off, I just new what the difference was and kept that in mind.

If you search, you can find what MPH a given rear gear ratio will produce at a specific engine RPM. I know there have been posts about that on here, and I have seen such charts on other mustang sites as well.
Mine was off between 5-10 depending on how fast your going.
Here's your link for MPH vs. RPM for different rear gear ratios:

http://www.bullittarchive.com/3013.htm

Pretty cool charts!
Bullittbabyc1796 said:
ok so how off will the speedo be 5mph or so
The speedometer will be off by 14%. The odometer will also be off by 14%. You will be reading more miles on the odometer than you actually traveled.
oh yeah, I didn't even think of the odometer. I am trying to keep the miles low....
It is hilarious driving with it not calibrated. I reflashed a tune once and forgot to plug in 3.73s and I drove on the highway. It said I was speeding but people were flying past me.
Might wanna invest in a tuner soon. That way it will take care of the calibration and you can play with the car a little more. If you plan on modding more you're gonna need one anyway..
Breaking news Im going to have to put the gears on hold.. Sad I know. But I just bought a 1997 Mitsubishi Eclipse Gs-t my dream car YAY.... Its a fixer upper "not running at this time" I'll get her started, I love Turbos... I really what a twin turbo kit for my Bullitt but $6000 umm thats not going to happen.
1 - 19 of 19 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top