AOD-2.73 to 3.73

[billheis]

Hey Willys, I've got a 90 vert with AOD and 373s Love it Make sure you get the 23tooth speedo gear. It will still be off by about 5mph. Like was mentioned you'll want to start saving up for a convertor. Ive got a full tilt Art Carr Aod & 2600 convertor sitting in the garage and can't wait to put it in ( Hey anybody in the North Jax or Nassua Co. area want to come help me put it in this week lol)

 

[mike keirstead]

cool, I dont know how many more the stock axles will take. I am currently hunting for a spool and 31 spline axles, cause more power is on the way this winter. I want to keep the car streetable as i drive it everyday.

 

[davs5.0]

Willys; you'll love teh new found acceleration. You won't believe the difference. I picked up 3 tenths going from 3.55's to 3.90's, so you should really see some improvment. What rpm stall is that PI converter you have? You may need some better tires for the strip if you don't already have some. My street tires are pretty much useless unless I really work the throttle.

 

[5.0_Junkie]

I am also running 2.73's with my 87GT AOD. It kicks ass! Turning 1500rpm at 60mph Please let us know what you think after you install them I am swithing to 3.73 over the winter. I have some 4.10 in a rearend but I think they may be too much for just a street car with ocassional strip use.
Anway post back.

Also with the 23 tooth speedo gear, the speedo will still be off. Is there something esle that can be done to correct the 5mph difference that you were talking about?

 

[davs5.0]

The only way to correct the difference in the speedo is getting the drive gear in the rear of the trans changed to a 7 tooth gear instead of the 8 tooth thats in there. You have to remove the tailstock of the trans to do it. And someone mentioned that it may be a machined part and not easily swapped. Check with your local tranny shop.

 

[plucka-plucka]

I got 3.73's this summer and I love them!! Very Streetable with lots of kick! Only problem is sometimes when it shifts into second the tires spin too much and then it goes into third and I am going nowhere quick!!! Have fun!
Rich-

 

[willys1]

Hey Willys, I've got a 90 vert with AOD and 373s Love it Make sure you get the 23tooth speedo gear. It will still be off by about 5mph. Like was mentioned you'll want to start saving up for a convertor. Ive got a full tilt Art Carr Aod & 2600 convertor sitting in the garage and can't wait to put it in ( Hey anybody in the North Jax or Nassua Co. area want to come help me put it in this week lol)

YEA DUDE,The mechanic just told me to get a new speedo gear,Where can I get one???I do have PI 2800 stall converter already in.(stallion)If the gears work 1/2 as good the converter,thats gonna be a quick little car!!

 

[willys1]

Willys; you'll love teh new found acceleration. You won't believe the difference. I picked up 3 tenths going from 3.55's to 3.90's, so you should really see some improvment. What rpm stall is that PI converter you have? You may need some better tires for the strip if you don't already have some. My street tires are pretty much useless unless I really work the throttle.

ITS a Precision Ind. 2800 stall speed(stallion)expensive, but well worth it!!!!!

 

[1hot5.0]

On the subject of correcting the speedometer after the gear swap, you also have the option of having a speedo box made. It is a box that plugs into your speedometer cable, and corrects the reading. My local speedometer shop wanted $180 installed. They said if they ever had to recalibrate it, it would be $30. It would be best to check with your local speedometer shop.

 

[davs5.0]

On the subject of correcting the speedometer after the gear swap, you also have the option of having a speedo box made. It is a box that plugs into your speedometer cable, and corrects the reading. My local speedometer shop wanted $180 installed. They said if they ever had to recalibrate it, it would be $30. It would be best to check with your local speedometer shop.

No local speedo shops up here in the great white north, at least in my area.

 

[billheis]

No local speedo shops up here in the great white north, at least in my area.

Hey Davs, 50resto.com and yearone.com carry the speedo gears. Youll still be little off but much closer than not changing.
Hey Willys, let us know how that pony is working now with your new stuff, hope you asked santa for some new tire lol

 

[Biggeley]

Hey Davs, 50resto.com and yearone.com carry the speedo gears. Youll still be little off but much closer than not changing.
Hey Willys, let us know how that pony is working now with your new stuff, hope you asked santa for some new tire lol

If you have a 89 or older AOD, there is a 7-tooth in there by default. With the 3.73's you will need a 21-tooth gear.

I have an 89 with a Lentech AOD, 2600 stall, and 4.10's.. It's a wild ride for sure especially this time of year with all the rain and light snow. hehehehe However for the track, I really need slicks for it to take advantage of the gearing. 3.73's are perfect for a street car.

Dave

 

[Michael Yount]

Here's a site with info about speedo calibration:

http://www.geocities.com/mgnedell/notchback/tech/speedo.html

 

[davs5.0]

I've already done the 23 tooth gear and unfortunately it didn't last very long. With the 3.55's I had, it was still off and the teeth being so thin on the 23, it only lasted a few months. I'm looking into the gear in the rear of the trans while its out over the winter.