I will start this Blog entry off with a cut and paste from an entry I recently posted on the forum.

The preamble:

I am not a fan of the non-mopar t5 transmission conversion. A great deal of those transmissions have gear splits that
were meant for low horsepower, low torque engines and they just do not match up well to a flathead mopar. The are also in my opinion, a great deal of work to make the conversion. There are many models of the T5 transmission, with several having very little overdrive to them. As some have pointed out, when I posted a chart showing a great deal of the T5 transmissions, in at least one case a member who is a huge t5 supporter, editted his post as his transmission was not what he thought it was.
That may should like a shot, it isn't meant to be, but what it is really is an illustration that a lot of guys have ventured into the t5 project without realizing what they are in for or what they even have. I do completely understand why so many having went though the conversion process, claim to be happy. They may indeed be, with all the work behind them and in some cases guys are not about to admit that they wished they have never went that route. At least one of those recently posted on the blog here, who was beyond frustrated with the project effort level and the results.

Now having said that, there are some t5 with better splits and more overdrive than others, but given the work effort, the cost and the end product it still wouldn't be my first choice.

The goal:

I wont go into the ramble on why I still prefer the Mopar Overdrive solution, and why for me the 1952-56 R10G Borg Warner overdrive gives you in essence a 6 speed transmission, and concentrate on the pursuit of many. That being a easier to
find Overdrive transmission that provides you with a decent level over overdrive, with a decent gear split and for many,
the desire to have a floor shift in their car.

There is also those with earlier (pre-1939) Mopar's that had a floor shift transmission and would like to keep that original cab look, but want an overdrive and cant find one of the floor shift overdrives from the 30's that came from Chrysler/Desoto.

The Solution:

A 1975 - 1987 Aluminum A833 4 Speed Transmission with overdrive.

Yes, the A833 "bullet proof" transmission is the in essence the same transmission as the "cast iron" version of the 60's that went behind the 426 Hemi. Those transmissions tend to be very pricy and 4th is direct drive 1:1 so since were looking for Overdrive, the older cast iron A833 doesn't fit the bill. Although the 1975- 1987 Aluminum A833 certainly does!

The details:

Lets start with for the earlier Plymouth we have to deal with the "X" frame so the A833 becomes a great candidate for this application.

I would use the Aluminum cased a833's 4 speed with overdrive which started part way into 1975 and went thru until mid 1987.

Here is the gear splits:

1st: 3.09:1, 2nd: 1.67:1 3rd: 1:1 4th: 0.73:1 (Trucks used a 0.71:1 fourth)

The overdrive configuration with a 23-spline input appeared in these vehicles:
o 1975 to 1979 Valiant, Duster, Dart, Scamp, Swinger, Volare, Aspen (3.09:1 ratio first gear)
o 1975 to 1987 Dodge light-duty pickups and Dodge and Plymouth Vans (3.09:1 ratio first gear)
o 1977 to 1979 Diplomat and LeBaron (3.09:1 ratio first gear)

The "Coles note" version of what you will need to do and I will mix in the details concerning the "X-Frame" which only becomes relevant in the models from the 1930's. You will be using the original bell housing, not the one that came from the vehicle
that had your donor A833 4 speed and yes ones like the bell housing in the pickups are large and might leave you
the impression your on the wrong track.
You will need and Adapter plate and screws to mount the transmission up to you stock bell housing. You do not
need to make modifications to your bell housing

* The Adapter plate kits (Plate and screws) are available from AoK. We do not have A833 transmissions for sale
You will need to change your clutch to fine spline and you will need to make an adjustment to the connection of the A833 transmission to the drive shaft. You can change the yoke on your drive shaft so it will connect up to the new transmission or in many cases this may be the opportunity to put in a modern rear end which will allow you to use a modern driveshaft with the A833 and the new rear end. Will talk about that more in a second.

** Note: Sept 2015 we sold the last Adapter plate and our Supplier cranks up the price to the point that we are looking for another
supplier. Will update this blog entry when we have more details.
Nov 2105 - as covered below, we have got a new supplier and have the adapters and bolts (as a kit) for $125 USD plus
shipping. That is the price for the next 25 at least and is priced really based on what the cost of the aluminum stock price is.

You do not need to change your pilot bushing as it is the same as original.

On 1937 – 39 Plymouth cars (with the X-Frame), you can cut bottom of x frame loop off - (half off) to get the transmission in place. Some think it is fine to leave it with the piece of X-Frame taken out, although it is easily to get it back in place so that would be my preference. The the last one I saw done, they made a bracket to put the x frame loop and then fasten the half of the X-Frame back in.

Depending on which A833 transmission you get, you may have to make a minor modification of the bearing retainer. It is the round plate that has 4 bolts holding it on to the tranny.. A couple of the A833's have a longer housing and you need to unbolt it and cut some of the housing off. About an 1” 1/8”,

For the 1937 we recently had a hand in, he used a 1966 dodge cornet rt clutch (10 ½”) and pressure plate that he bought from napa (called a clutch pack), however there are lots of great and inexpensive options there.

You can change the yoke on the drive shaft to hook up to the A833 or change the rear end.

For the 1937 Plymouth project I just mentioned, he put in a 1963-64 Chrysler New York rear end and it fit in perfect. It also had 3” x11” brakes and positraction and a 3:55 rear end ratio which with the a833 gives you 2.59 results as well gave you the emergency brake on the rear axle since you loose the emergency brake drum when you swap out your original transmission.

Here is a handy chart on mopar rear ends that may come in handy depending on your application

For the 1937 Plymouth which already had a floor shift, the shifter had to be modified slightly so it came up in the original position. Basically the shifter was modified to move it to the right (passenger side) and then up towards the firewall slightly ,to have it come up the original shifter position. Despite the two bends it shifts perfectly.

If you are putting the A833 in an early pickup the shifter had to be modified to go towards the passanger 3/4" and then towards the firewall 1 1/2 and it shifts perfectly. In the pickup if your interested, when the snow leaves (about july.. lol) I have to go have a better look at the rear end. I cant remember if the drive shaft was modified to put the modern yoke or if the rear end was changed. I do know the A833 came right out of my Dad's 1982 Dodge pickup.

The net in either gives you a floor shift transmission with decent overdrive ratio (0.73:1 or on the Trucks 0.71:1) and decent gear splits!

For cars from the 1940s and 50's you don't have to deal with the "x-frame" so the project is even simpler. In terms of the shifter position coming through the floor, you will have a slightly better starting point than other modern floor shift transmissions, and keep in mind you can modify the shift to bend it towards the passenger if you like or towards the firewall.

Personally in a 1948 Plymouth business coupe, we made no modification left (towards the passenger side) but bent it forward towards the firewall a bit just because for the driver (6 foot 2 inches) that is just where it felt the best. The point being you have a fair amount of flexibility in where you want the shifter to come up through the floor and then bend it to work best for you. For the 1946-48,Plymouth it seem the US cars may have a slightly different back mount with a cross over member being notched for the standard 3 speed. To then accommodate the lower a833 transmission, I am told you have to notch that cross over frame piece slightly to use the adapter and A833 transmission. For the 1948 Canadian Plymouth we did not have that issue.

* Jan 2016 - We have been able to pull stock transmission out of 1946-48, 1949, and 1950 Plymouths made in USA and every
one would require modification of the cross member as the A833 4 speed being deeper than the stock
transmission is going to hit the cross member..

Also remember that when you swap out your original transmission and move to any modern transmission, you have to consider what
your doing for an emergency brake. As I covered above, the change of the rear end to a more modern rear end may solve that problem for you. There other options,

1 such option would be something like - E-Stopp Electric Emergency Brake with Remote Push Button

http://www.estopp.com/

Here is the A833 illustration right from Dodge/Chrysler and then a view angles of a rebuilt tranny.

** Dec 22 2015 - Just to be clear, the A833 adapter plate is for Mopar 833 Aluminum 4 speeds for use in Mopar cars, and was not designed for use with the - 1981 -1986 Chevy/GM Truck Overdrive which I believe is a 833/RPO MY6. We were contacted in May by a customer and in the conversation it became apparent he was considering using a GM version of the transmission and he was told there appears to be a great deal of difference between it and the Mopar version of the A833. It appears he has been able to make modifications and get it to work and we will attempt to get a report from him, but up until now we have had zero experience trying to use
A833 chevy truck transmissions with this adapter. That doesn't mean that this conversion cant be successful, but it does mean we don't have experience in doing this.

There also appears to be interest in an adapter plate for the lighter truck bell housings, which as of now our adapter plate would be viable only for the 1955 and newer 1/2 tons using the column shift 3 speed and utilize the car style bell housing. The floor shift heavier 3 speed and lighter for speed (top bell housing below) and the heavier 4 speed in the 1 ton and lighter 2wd trucks with heavier 4 speeds that utilize the offset bell housing (bottom bell housing below) will not work with our current adapter plate and an a833 mopar 4 speed.
Depending on demand we can make adapter plates for either. Let us know if you are interested.

Feb 5 2016 -

Well mission accomplished. We now have an adapter plate for the both heavy 3 speed floor shift and light 4 speed bell housings and heavier 4 speed bell housings. Bellow is the truck adapter which works for both, then a picture of it with the car and light 3 speed column shift for tucks, and then a picture of the two truck bell housings that the new adapter plate works with. Price is going to be $135 & shipping for the kit. The kit will be the adapter plate and 4 bolts required to mount the adapter plate to the truck bell housing.

Bottom line: In the continental United States car adapter plates are $140 shipped and truck adapter platers are $150 shipped. Outside of that area cars are $125 + shipping and trucks are $135 + shipping.