Exhaust and gears on an AOD

91AOD5.0LX

I have a slight sag in my rear
Feb 20, 2021
202
110
53
North East
Hey guys - I’m new to the board. I see there are lots of discussions regarding exhausts and gear selections which were very helpful. Many of the discussions are in regards to highly modified stangs so I am curious to see what you guys would say about my below intentions with a stock stang.
So I picked up a 1991 LX AOD in Dec. it’s 100% stock with 2:73 gears. The car has 111,000 miles on the clock and seems to run fine. Just no power and missing that great old school 5.0 rumble.
I'm excited to get the gears and exhaust done very soon. I have an O/R H-Pipe lined up with a cat-back Flowmaster super 44 system and a set of 4:10s to swap out the 2:73s. Remember, it’s an AOD and the car is not a DD. My intentions are to take it out maybe a few times a month to local parking lot “shows” for enjoyment. No racing, just looking for a great sounding loud but not obnoxious rumble and some quick acceleration off the line if I’m in the mood to feel a little power here and there. Lol
My set-up can be changed so before I do so I’d be curious to hear some comments, opinions, critic, advice, etc from anyone with an AOD and a comparable set-up.
stay safe everyone and thanks in advance for any discussion.
 
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mikestang63

SN Certified Technician
Aug 27, 2012
10,220
7,006
204
In the garage
3.73 or 4.10's . Couplee that with a good shift kit or Silverfox valve body and it will be a different car
 
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91AOD5.0LX

I have a slight sag in my rear
Feb 20, 2021
202
110
53
North East
3.73 or 4.10's . Couplee that with a good shift kit or Silverfox valve body and it will be a different car
Thanks Mike! Shift kit will likely be next. I’m thinking the 4:10 upgrade alone should make it a differant car as well but I’m not sure just how much of change to expect initially. Hope I’m not over exciting myself as I am expecting it to be drastic. That’s why I was real curious to get opinions on these initial upgrades and then other mods will follow in time. Thanks again!
 

91AOD5.0LX

I have a slight sag in my rear
Feb 20, 2021
202
110
53
North East
If no racing, 3.73s.

if you do a lot of highway driving I’d say to even consider 3.55s.
Thanks for that. Definitely between the 3:73 and 4:10 because highway driving is super minimal and a matter of fact even local driving will be kept to about 2,000 miles a year. That’s why I was thinking 4:10s especially being and AOD but 3:73 is still on my mind as well. Its great to hear the different thoughts from everyone. Thank you! Really looking forward though in dropping it off with the Stock exaust and 2:73 then picking it up with 3:73/4:10 and an o/r pipe with 2.5” super 44s. Really hoping for it to jump with a mean sound and be a totally different car that makes me say WTF. Curious how accurate you guys think my expectations are? Lol
 

Rdub6

So while I wait to figure out my rear end issues
Dec 29, 2017
2,442
1,788
133
Long Island, NY
It will feel and sound like a different car, and be more fun. But it’s still going to be a 200hp (if that) stock motor, so don’t get your expectations too high!
That being said, having fun is what it’s all about, so I’m all for it! Good luck!


And let’s see some pics!
 

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
36,122
12,039
224
Massachusetts
Went I went from 2.73 to 3.73 in my car when it was AOD it was like a totally different car.

it was a monster from 0-60mph, but 60-100 it felt like I was winding the hell out of the (stock) motor but not really going anywhere.
 

91AOD5.0LX

I have a slight sag in my rear
Feb 20, 2021
202
110
53
North East
It will feel and sound like a different car, and be more fun. But it’s still going to be a 200hp (if that) stock motor, so don’t get your expectations too high!
That being said, having fun is what it’s all about, so I’m all for it! Good luck!


And let’s see some pics!
Beautiful! Fun is exactly what I am looking for so that info excites me. Thank you and i totally understand the stock 200hp part as well. Makes sense.
picture attached
 
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Rdub6

So while I wait to figure out my rear end issues
Dec 29, 2017
2,442
1,788
133
Long Island, NY
Beautiful! Fun is exactly what I am looking for so that info excites me. Thank you and i totally understand the stock 200hp part as well. Makes sense.
picture attached
Wow, that’s nice and clean! Is the interior in as good shape as the outside?
 

91AOD5.0LX

I have a slight sag in my rear
Feb 20, 2021
202
110
53
North East
Went I went from 2.73 to 3.73 in my car when it was AOD it was like a totally different car.

it was a monster from 0-60mph, but 60-100 it felt like I was winding the hell out of the (stock) motor but not really going anywhere.
Ok this is great information because that is exactly what I would be looking for. A monster in the low mph range and not overly concerned with the 60mph and up performance because I’m mostly just going to be buzzing around town and not looking for a race or high speed driving. Lol The car is old and high miles so really looking to keep her clean and not blow the motor or anything like that. Lol just some local enjoyment with a deep rumble and feeling that if i hit the peddle she’s gonna move because right now she doesn’t! Lol just want to have a little fun cruising on my own and meeting up on weekends with other stangs. therefore what you said is really perfect for what I am looking for. It’s nice to hear from guys that know and that have done this already. Thank you!
 

91AOD5.0LX

I have a slight sag in my rear
Feb 20, 2021
202
110
53
North East
Wow, that’s nice and clean! Is the interior in as good shape as the outside?
Thank you. I appreciate that. The interior is pretty clean. Does need some scrubbing when the weather gets warmer around here and I picked up some SEM Titanium paint to spray and make everything match. I have the 5 different shades of gray thing going on right now. Lol lots to do when the snow goes away over here.
 

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KRUISR

5 Year Member
Apr 16, 2015
767
285
83
51
I have an AOD with a Lentech VB in an otherwise stock tranny. I have 3.73 gears as well.'

Something to consider when deciding between 3.73 and 4.10s... when I left from a traffic light with light to part throttle, first gear is done almost immediately. It shifts to second around midway through intersection. If I had 4.10s, I think it would be worse.

First engine I had was basically stock with 1.7 RR and Explorer intakes, injectors and TB and full 2.5" exhaust. That was it. It was a blast to drive and worked great.
 

91AOD5.0LX

I have a slight sag in my rear
Feb 20, 2021
202
110
53
North East
Thank you Kruisr! Great info. What you described with the quick shifting before your out of the intersection is definitely something I was concerned about as persons I spoke to explained the same. Im glad to hear it from you though being that you actually have an AOD with the 3:73s. Those persons I spoke with spoke from knowledge they had but not 1st hand as they didn’t actually own an AOD themselves. It’s just info they repeated. I did figure 4:10s would shift that quick. Question to myself though is if I’d mind that or not. That’s the hard part. If it were a DD then the answer for me would definitely be a no-go for the 4:10s. Being that it’s going to be an occasional driver I’m more tempted to “not fear the gear” (lol) as they say but I’m still trying to be smart and realistic about the decision and therefore your points are very well taken and for sure making me think again. Urrrrr it’s never easy. Lol
Thanks very much for your input!
 

Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
36,122
12,039
224
Massachusetts
I remember mine used to chirp 2nd gear regularly after the 3.73s at WOT. Was pretty fun to do.

IIRC, my best time on the AOD was a 14.2 @ 96MPH with 3.73s, cobra intake, BBk headers, cat-back flowmaster, pullies and e-fan. Car was speed density and ran very strongly. Did the 1-D-1 shuffle all the time with it. I 5-spd swapped it some time after that.
 

91AOD5.0LX

I have a slight sag in my rear
Feb 20, 2021
202
110
53
North East
I remember mine used to chirp 2nd gear regularly after the 3.73s at WOT. Was pretty fun to do.

IIRC, my best time on the AOD was a 14.2 @ 96MPH with 3.73s, cobra intake, BBk headers, cat-back flowmaster, pullies and e-fan. Car was speed density and ran very strongly. Did the 1-D-1 shuffle all the time with it. I 5-spd swapped it some time after that
Banging out a chirp is always fun! Addicting actually.
my exhaust and gears will be done by the end of March so for those interested I will post an update a few weeks from now letting you know what i decided on and how it compares to its before and now after.
 
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91AOD5.0LX

I have a slight sag in my rear
Feb 20, 2021
202
110
53
North East
Good info. I tell ya the more research I do the more complicated it seems to get. Lol
Now I’m looking at off road X pipe vs off road H pipe. Not regarding power differences or anything else like that. Interested in the best sound. Seems one is louder than the other and one is more “European” sounding as they say vs old school muscle sound.
I don’t want it obnoxiously loud. Just a nice loud awesome sounding car but not rediculous.
I know, I’m all over the spectrum. Haha got the car in December so it’s all new to me and trying to figure it all out and learn.
Any thoughts on the X vs H sounds?
 

KRUISR

5 Year Member
Apr 16, 2015
767
285
83
51
get you a better converter too ....3.73 is fine .. I run a rebuild AOd with PA Valvebody, TCI 10 inch Converter and 373..now with Nittos 275/50-15..and that works pretty good..
I think the converter is only NEEDED if you plan lots of hard launches (say drag racing). If just street cruising or spirited driving it is not needed.

A valve body/shift kit for me are more important than the converter. I still have stock converter but with Lentech VB. Nice firm (chirp the tires) shifts, eliminates the 1-D-1 shuffle.
 
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Zeffer

Member
May 27, 2020
2
1
13
Mission B.C.
I have an 89 hatchback, AOD, bone stock internals, Explorer upper intake, BBK equal length shorties, off road h pipe, super 44's, 65mm tb and fenderwell cold air wirh a bbk maf, 19lb injectors. This is the way I bought the car, it was fun, but....I added 4.10's after a lot of reading on here, and I have to tell you, it made this a different car!!! In my car I'm going to get a Lennttech valve body and a 2500 stall convertor after I rebuild the trans. I have the engine and trans out now, just got the block back yesterday and am going to start assembling it....now it's a 347
 
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91AOD5.0LX

I have a slight sag in my rear
Feb 20, 2021
202
110
53
North East
Yep in my case it’s just for occasional street cruising so im going to start with just the gears and exaust and hold off on any other mods for later and if my usage changes but for now it’s a once in a while cruise around the blocks for 20 minutes and then back to the barn. Lol thanks guys for the advice and input