best gears for AOD turbo fox - Ford Mustang Forums : Mustang Forum
  • 1 Post By hulk8950
  • 1 Post By t32265
  • 1 Post By TomR
LinkBack Thread Tools Display Modes
post #1 of 11 Old 05-16-2018, 09:04 AM Thread Starter
Registered User
91NotchCoupe's Avatar
Trader Feedback: (0)
Join Date: May 2018
Location: South Jersey
Posts: 2
best gears for AOD turbo fox

hey all, ive got a 91 notch AOD car. this thing is a dog pretty much all stock. im ordering up a turbo kit, and a few other supporting things for it. just curious on best rear gear ratio for a turbo foxbody with an AOD. i know the rule of thumb is usually 4.10 aod and 3.73 t5 cars. ive done some research and most people seem to stay with either stock 2 something gears or go to 3.55 when turbo'ing the car.. this car is not a DD and driven on weekends around town. was thinking of doing a 2800-3k Stall non lock up converter and 3.55's and full manual VB... anyone have any input on that decision ? thanks!

91NotchCoupe is offline  
Sponsored Links
post #2 of 11 Old 05-16-2018, 09:21 AM
Registered User
hulk8950's Avatar
Trader Feedback: (0)
Join Date: Apr 2006
Location: columbia city
Posts: 71
3.27 or 3.31's... Also gut that AOD and fill it with all 4r70 internals with a 1pcs input, good valvebody and of coarse a good converter.

wytwolf likes this.

'89 TTGT 306, canfeilds, F-cam, 1.6rr, edelbrock perf intake, 76 C&L, 65mm TB, 42# inj, self fab'd twin T60's, MSD 6AL, stock ECU(no chip/ piggyback), home built C4, 3.50 gears, 9", 27X10.5's, 3500#, 9.94/136mph on 14psi
hulk8950 is offline  
post #3 of 11 Old 05-16-2018, 11:06 AM
Registered User
Trader Feedback: (4)
Join Date: Dec 2010
Location: Dallas/Houston
Posts: 1,755
I have 2.73's and first never hooks, second sometimes hooks up top, and I'm on an ET Street Drag Radial. OD drops RPMs nice and low for highway use. If I was going to hit the track a bunch, I'd probably do a 3.27, and still might consider doing this down the road.
5.0thunder is offline  
Sponsored Links
post #4 of 11 Old 05-17-2018, 03:04 AM
Registered User
t32265's Avatar
Trader Feedback: (16)
Join Date: Oct 2012
Location: Casselberry Florida
Posts: 485
Figure out your speed at the end of the track and gear accordingly, BTW I ran 3.73 but only ran 1/8 mile and hit the traps at 6800
TomR likes this.
t32265 is offline  
post #5 of 11 Old 05-18-2018, 04:27 PM
Registered User
Radrick50's Avatar
Trader Feedback: (60)
Join Date: Aug 2000
Location: Altoona, PA, USA
Posts: 1,768

93 Notch 347 twin 66s TH400...8.54 @ 162 Radials

91 Notch 410W Novi 2000 5 speed...10.99 @ 136
Radrick50 is offline  
post #6 of 11 Old 05-31-2018, 04:01 AM
Corral Elite Member
wytwolf's Avatar
Trader Feedback: (8)
Join Date: Feb 2012
Location: CA, OR, WA
Posts: 796
3.27 here, 89 Notch, Dart 331, 76mm midframe
wytwolf is offline  
post #7 of 11 Old 05-31-2018, 08:10 AM
Registered User
Trader Feedback: (1)
Join Date: Dec 2015
Location: Rush, NY
Posts: 2,428
I read someplace that 3.31's have the lowest friction losses and best power through put. In the search for every last MPG to satisfy the Fed's, I'd believe it. Anyway, I'd be looking at 3.27's or 3.31's.

Also, with a turbo, I don't know as if the 4R70W internals are worth the effort. N/A or supercharged I would say it's worth doing. Everything I've read says turbo like to be loaded. The AOD gearset will load more than the 4R gearset with the same ring and pinion out back.
tjm73 is offline  
post #8 of 11 Old 06-02-2018, 08:26 PM
Registered User
midnightlaundry's Avatar
Trader Feedback: (3)
Join Date: May 2004
Location: Westland, MI.
Posts: 2,142
If you drive on the highway a 3.55 would be a good compromise.

A 3.55 would put you at 45mph at 6000 rpms in 1st gear. That's about the same as a 3.27 on a 5-Speed TKO. 2nd would put you at 83mph at 6k compared to 71mph on a TKO with a 3.27.

You'll definitely cross the finish line in 3rd, so if that's you're main goal than a gear that puts you near your peak power thru the line is where it's at like others have said. BTW, you need less Camshaft with a Turbo. Don't go to big.

Here's an easy Calculator. YOu can drag the slides to see where you're mph would be..
midnightlaundry is offline  
post #9 of 11 Old 06-04-2018, 04:41 PM
Registered User
TomR's Avatar
Trader Feedback: (2)
Join Date: Aug 2009
Location: Macon, GA
Posts: 4,947
The gear depends on your finish line MPH and RPM, if you can manage boost, and how your car hooks. It also depends on low gear ratio and your torque converter.

What works for one person's system might not be good for another.

I run a 4.10 gear but my car is a different car than yours.

If I were in your shoes I would run the car with the gear it has and see where I was at. It's a little silly to change gears just on a wild guess. Build it, tune it, see where you are at. The manual valve body will be fine.

The higher stall with a turbo means a lot more than any rear gear change you will make. You will probably be fine except for the carrier and the axles. I would be wanting some 31 spline axles more than a gear. Those 28 splines are pretty weak in the carrier and real weak in the axle.
Radrick50 likes this.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
89 LX. 363, single turbo, Super Vic EFI, TFS high port heads by TEA, solid roller, glide. Holley HP EFI. (exact combo varies)
TomR is offline  
post #10 of 11 Old 06-23-2018, 04:13 PM
Registered User
Trader Feedback: (22)
Join Date: May 2006
Location: California
Posts: 1,259
I built a twin turbo 393w and decided to go with 3.31ís, Iím running a Lentech Strip 4r70w, havenít made it out of on the road to give a real world review yet FWIW.

turboLXstang is offline  
post #11 of 11 Old 06-23-2018, 07:58 PM
Registered User
mld54's Avatar
Trader Feedback: (1)
Join Date: Mar 2002
Location: Lexington Ky
Posts: 309
I have 347 with a built 4R70W, 76 mm turbo and a 9 inch in my car. I have run a 3.50. 3.25 and now a 3.80. I like the 3.80 the best. The car is more fun, feels stronger and gets better milage with the 3.80.

93 Mustang Coupe, Turbocharged Dart 331, 4R70W, Moser 9in, Haltech, Flexfuel
mld54 is offline  
Sponsored Links


Quick Reply

Register Now

In order to be able to post messages on the Ford Mustang Forums : Mustang Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Similar Threads
Thread Thread Starter Forum Replies Last Post
Want To Trade Fox Cobra Clone turbo project n8secstangg Mustangs For Sale/Wanted, 1987-1993 1 07-17-2017 11:41 PM
For Sale Twin turbo kit for Fox 5.0L SonicFox Power Adders 5 07-20-2013 11:14 PM
Hp Performance Fox Mustang Turbo Kit Fitment Problems NWJason Turbochargers 45 04-01-2011 10:57 PM
For Sale Custom Turbo Kit 76mm turbo complete Fox Body nochance Power Adders 17 12-14-2010 03:18 PM
What gears go best w/ a Turbo? jwdgt23 5.0/5.8 Engine Tech 2 12-06-2001 03:14 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome