What 8.25 rear axle fits my 1964 Dodge Dart best?

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Arend Huisman

Arend Huisman

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Hi there,

it seems my 7.25 diff is shot and there are just no replacement parts. Next to that, i replaced the 273 in my car for a 318 and it would be better to replace the complete rear axle for one with a 8.25 diff. Which is the one to go looking for?
 
Arend Huisman said:
Hi there,

it seems my 7.25 diff is shot and there are just no replacement parts. Next to that, i replaced the 273 in my car for a 318 and it would be better to replace the complete rear axle for one with a 8.25 diff. Which is the one to go looking for?
Click to expand...
Click on the Forum title "Transmission and Drivetrain Tech. All the threads in yellow are called "stickys" and stay at the top of the list at all times. There is a rear axle chart there.
 
An 8 1/4 out of a '73-'76 A body will be the correct width for your '64.
HOWEVER-
-You will need new shock plates and U bolts; the axle tube diameter is larger than your 7 1/4.
-You will need to shorten your driveshaft or have a new one made; the 8 1/4 has a longer nose, so it requires a shorter driveshaft (IIRC it's about 1 1/2- 2" shorter, do some searching for the exact number- there's lots of threads on this). Your '64 uses a ball and trunnion transmission output instead of a slip yoke and it may be difficult to find a shop that can still build a new one, so shortening your existing driveshaft may be your only option. There is a mod for building a new shaft, detailed here: https://www.earlycuda.org/techdocs/ConvertFrontUJoint.pdf
-With the 8 1/4 you will have the 5x4.5" bolt circle, which won't match the 5x4" bolt circle you have on the factory front brakes.
-The parking brake cables are different, but can be made to work.
 
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Just remember, with the 8 1/4, you'll be going from the small bolt pattern to the big bolt pattern so you'll need different wheels for the rear. Also, the F body 8 1/4 will "fit", but the spring are like 1/2" wider apart. You can just push the springs out a little on each side and it will fit. I don't endorse that, but plenty of people have done it.
 
Thanks you for this info, that's a big help!
I found out that a lot of a-bodies between '69 and' 72 have a 8.25 diff as well as the right, 5x4 bolt circle...
 
Arend Huisman said:
Thanks you for this info, that's a big help!
I found out that a lot of a-bodies between '69 and' 72 have a 8.25 diff as well as the right, 5x4 bolt circle...
Click to expand...
No, you didn't. The first year for the 8 1/4 in a A body was 1973. What you found was bad information. The 8 1/4 never came with the 5x4 bolt circle.

Now, having said that, all of the information I just told you is regarding AMREICAN made vehicles. Regarding vehicles in other countries, you could well be right. That's information that you should share where you found it. That would be a good addition to this site.
 
Arend Huisman said:
Yes, i see now that you're right. I jumped to conclusions too fast.
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It appears you're in another country though. So, all bets are off, unless you've found that our information is the same as yours. That's not always the case. As an example, slant six engines were made up until about 2000 in some countries. Here, the last year was about 1987. So who knows? It worth doing some research on for sure. If you find an 8 1/4, just know they are pretty tough rear ends ans can probably take most anything you can throw at it as far as a street car goes.
 
an australian valiant axle will also fit its a robust (pre1970 7 1/2) post 1970 7 3/4 inch axle used behind 225 all the way to 360. granted they broke a few but very well regarded the US IROC camaro/ ta firebird had one on coil springs 82-92

i have no idea if netherlands had australian valiants, unlikely as they are RHD, but you did have belgium assembled barracudas and potentially spanish dodges both of which might be a source of a better axle

Dave
 
Dave999 said:
an australian valiant axle will also fit its a robust (pre1970 7 1/2) post 1970 7 3/4 inch axle used behind 225 all the way to 360. granted they broke a few but very well regarded the US IROC camaro/ ta firebird had one on coil springs 82-92

i have no idea if netherlands had australian valiants, unlikely as they are RHD, but you did have belgium assembled barracudas and potentially spanish dodges both of which might be a source of a better axle

Dave
Click to expand...
I'm unsure "robust" should be used to describe any rear axle with a ring gear under 8" in diameter.....but I kinda get what you're saying. lol
 
well i had to use robust because they are the "little axle that could" materials used were excellent and QA was good

perfect low loss axle for hemi 6 and slant 6 racers. light weight, easy to turn big thick ring gear everything from spool through locker to clutch cone and torsen centres
25 28 and 31 spline shafts

borgwarner design, the later ones used same 28spline as some of the ford 9 inch units

apart from the axle tubes occasionally coming off, when drag raced to death, they tend to live longer than their diminutive size would suggest.
the cone LSD centre was cast steel in some cases rather than nodular iron...!

they tried hard... :)

2.77:1 4 pinion cone based LSD used behind the 727/360 combo in the luxury cars

ford ran em behind 6 and small block v8

2 litre turbo skyline
4 litre TVR
4 litre morgan
v8 firebird and IROC Z

basically just about everything in Oz and SA used a borg warner M series axle
m75 7 1/2 M78 7. 8 inch

i've got Moser axles and true track style centre in mine... :) and it would fit under the rear end of a pre 68 B body due to Aussie A body rear end width after 1971


obviously NOT 8 3/4 strong but very much better than a 7 1/4

they did an M88, sounds great, 8.8 inch ring gear, and fits an A body just a rare thing and you can't get parts.

all now little known products of Spicer Axle Australia/Dana Corp.
 
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Dave999 said:
well i had to use robust because they are the "little axle that could" materials used were excellent and QA was good

perfect low loss axle for hemi 6 and slant 6 racers. light weight, easy to turn big thick ring gear everything from spool through locker to clutch cone and torsen centres
25 28 and 31 spline shafts

borgwarner design, the later ones used same 28spline as some of the ford 9 inch units

apart from the axle tubes occasionally coming off, when drag raced to death, they tend to live longer than their diminutive size would suggest.
the cone LSD centre was cast steel in some cases rather than nodular iron...!

they tried hard... :)

2.77:1 4 pinion cone based LSD used behind the 727/360 combo in the luxury cars

ford ran em behind 6 and small block v8

2 litre turbo skyline
4 litre TVR
4 litre morgan
v8 firebird and IROC Z

basically just about everything in Oz and SA used a borg warner M series axle
m75 7 1/2 M78 7. 8 inch

i've got Moser axles and true track style centre in mine... :) and it would fit under the rear end of a pre 68 B body due to Aussie A body rear end width after 1971


obviously NOT 8 3/4 strong but very much better than a 7 1/4

they did an M88, sounds great, 8.8 inch ring gear, and fits an A body just a rare thing and you can't get parts.

all now little known products of Spicer Axle Australia/Dana Corp.
Click to expand...
I have no doubt they are "robust" compared to the 7 1/4. Most everything is. lol
 
You can also use an 8.8 differential sourced from a mis 2000s Ford Explorer. There are threads on the forums that will detail the parts and process, it will need to be shortened of course, but is very stout, and comes with disc brakes, 5 on 4.5 bolt circle, typically a Traction Lok (Fordspeak for Sure Grip) carrier, and either a 3.73 or 4.10 gear ratio. I have no idea what availability is going to be like in the Netherlands however.
 
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Dave999 said:
well i had to use robust because they are the "little axle that could" materials used were excellent and QA was good

perfect low loss axle for hemi 6 and slant 6 racers. light weight, easy to turn big thick ring gear everything from spool through locker to clutch cone and torsen centres
25 28 and 31 spline shafts

borgwarner design, the later ones used same 28spline as some of the ford 9 inch units

apart from the axle tubes occasionally coming off, when drag raced to death, they tend to live longer than their diminutive size would suggest.
the cone LSD centre was cast steel in some cases rather than nodular iron...!

they tried hard... :)

2.77:1 4 pinion cone based LSD used behind the 727/360 combo in the luxury cars

ford ran em behind 6 and small block v8

2 litre turbo skyline
4 litre TVR
4 litre morgan
v8 firebird and IROC Z

basically just about everything in Oz and SA used a borg warner M series axle
m75 7 1/2 M78 7. 8 inch

i've got Moser axles and true track style centre in mine... :) and it would fit under the rear end of a pre 68 B body due to Aussie A body rear end width after 1971


obviously NOT 8 3/4 strong but very much better than a 7 1/4

they did an M88, sounds great, 8.8 inch ring gear, and fits an A body just a rare thing and you can't get parts.

all now little known products of Spicer Axle Australia/Dana Corp.
Click to expand...
That looks like a very good solution! Would you know a nice one for sale? What I also like is are the 25 spline (in which my axles would probably fit) and the 2.77:1 which give my car the nice 1800 rpm at 60 mph...
 
Arend Huisman said:
That looks like a very good solution! Would you know a nice one for sale? What I also like is are the 25 spline (in which my axles would probably fit) and the 2.77:1 which give my car the nice 1800 rpm at 60 mph...
Click to expand...
what years are we talking about and where should I look for one?
Not afraid to make a nice trip to GB... ;)
 
Just for the heck of it....I got on Google Maps and checked Burgum to London. 7 hours and 57 minutes. Seems like a good road trip. Does the EU let you cross borders without it being a big deal?
 
That is not a big problem. I visited London 2 month ago with friends, we went through the tunnel, saw Jamie Cullem and had a blast!
 
If you are happy to come to the Uk you can probably find a 7 1/4

and i'll ask about australian axles

to fit direct you will need a pre 1971 valiant axle.. with 5 on 4 inch PCD


sign up to forum here and ask or i can ask for for you www.moparuk.com
you then have access to a range of people who have been into mopars for years or who run businesses linked to the hobby. post in wanted section.
or try calling Duncan Watts, Watts Racing Transmissions in Crewe, Cheshire 01270 580637
or 07974 088375. Dave Billadeau, Billadeau Speed & Automotive

both import mopars dismantle mopars and build race cars

Duncan is a transmission specialist
Dave does race engines
both have parts for sale a lot of the time

to import used stuff to UK/ europe from USA try Ron Fenton at STS imports, 40 foot container every 6 weeks https://www.stsimports.co.uk/

to buy a "built" axle from the USA try Chris Goodale
Goodale American Speedshop - UK



Dave
 
RustyRatRod said:
Just remember, with the 8 1/4, you'll be going from the small bolt pattern to the big bolt pattern so you'll need different wheels for the rear. Also, the F body 8 1/4 will "fit", but the spring are like 1/2" wider apart. You can just push the springs out a little on each side and it will fit. I don't endorse that, but plenty of people have done it.
Click to expand...
F body rear is also over 3" wider (60.46" wide IIRC). at least around me, anything pre 1990 is just not out there anymore, especially in junkyards. a pre '93 ford Ranger 8.8 will be about the same width as the A body rear (my duster's 8 1/4 is 57.125" wide, early rangers are I think 57.5"), or an explorer with one side shortened to center the pumpkin using 2 passenger side axles (I think that ends up being about 56.6" wide)...never mind, just realized you're in europe
 
michiganpat said:
F body rear is also over 3" wider (60.46" wide IIRC). at least around me, anything pre 1990 is just not out there anymore, especially in junkyards. a pre '93 ford Ranger 8.8 will be about the same width as the A body rear (my duster's 8 1/4 is 57.125" wide, early rangers are I think 57.5"), or an explorer with one side shortened to center the pumpkin using 2 passenger side axles (I think that ends up being about 56.6" wide)...never mind, just realized you're in europe
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That's correct, but the spring perches are not. They are 1/2" wider apart than the A body. And as I said, they WILL swap in, but why anyone does it, I haven't a clue, since you lose a lot of room on that outside wheel well. Then there's the slight bind the springs are in. It's just not a good idea, IMO, even though a lot of people do it.
 
RustyRatRod said:
That's correct, but the spring perches are not. They are 1/2" wider apart than the A body. And as I said, they WILL swap in, but why anyone does it, I haven't a clue, since you lose a lot of room on that outside wheel well. Then there's the slight bind the springs are in. It's just not a good idea, IMO, even though a lot of people do it.
Click to expand...
yeah, IIRC they're 42.46" due to the splayed (not parallel) rear springs. B body is 43", I had to get a little creative when I swapped a B body rear into my M 20 years ago....cutting, relocating and welding spring perches is easier than dealing with an axle way too wide
 
up Thanks for everybody's input! As for now Robbert (my magic mechanic, has reorganized the original set-up for now, with the best components we had lying around. We hope this will last until we find a nice 8.25 rear axle.

I will start a new thread "looking for 8.25 rear axle complete, for Dart 1964". I'm sure someone here knows exactly which one will fit the best.
 
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