9" rearend

[THMPN73]

lots of people put a ford 9" diff in there cars and i was wondering how they got the wheels to fit...
will dodge bolt pattern wheels fit on a ford 9"?

[deputycrawford]

As a general answer, yes, Chrysler and Ford generally had the same bolt pattern. Check on the specific rear end you purchase to see if it has been been modified at one time or its for the correct application. It should come out to be 5 by 4 1/2 in. I would like to ask why you don't consider the Chrysler 8 3/4? The ring gear is only a 1/4 inch difference and is reported to be just as strong in most applications. It was even used under Hemi automatic B bodies. You can find them everywhere and the project would be direct bolt in. Just curious. 

[THMPN73]

i have noticed the 8 3/4 rears to be quite a bit more expensive

[THMPN73]

also is it hard to install your own gears? or is that something to leave to the real mechanics

[THMPN73]

i have come up on another question.
I noticed there are 28 and 31 spline ford 9" does it really make a huge difference
will be running approx 400 hp

[deputycrawford]

Oh yes, go with the 31 spline. The more splines the more to grab the axle. 8 3/4 have 30 spline stock. They also load exactly like the Ford 9 in. A Chevy person could not even tell them apart. They look that much alike. I have a spare pig laying around with with a 3.23 sure grip in it. 4.10 around town, 3.23 for the road trips. I can change it in about an hour total.

[THMPN73]

well i have an overdrive tranny and a 28 in. tire so I should still have reasonable revs on the highway with 4.10s.
but what are the chances of a 28 spline axle failing? im a student on a tight budget so for now i just want something cheap that will help me get into the 13s.
I have been running a 8-1/4 diff for a couple years with lots of abuse and no problems...how many spline is that diff?

[deputycrawford]

A 28 spline axle will do 13's. The speed bug will chomp your head off and you will need a Dana with 35 spline axles and a 4.88.

[THMPN73]

are danas good for racing? i heard that they are really heavy and mostly used for 4x4

[Chryco Psycho]

also is it hard to install your own gears? or is that something to leave to the real mechanics

it requires special tools & a press to set up gear sets in carriers
I Far prefere the Dana , they have 35 spline axles , are far stronger then the Ford 9 & require much less power to turn them , you can usually get a Dana 60 with a 4.10 gear ratio , sure grip etc for $100 at a wreckers from a Ford truck  , then you just need to shorten the housing & order axles , the brakes will fit off the diff you now have & it should run around  $1000 total ready to bolt in 

[Ghoste]

The Dana is heavier but it is also heavier duty and that strength has to come from somewhere.  They are worth it and they probably have just as much aftermarket support as the Ford 9 inch (which in my opinion is really the only reason to consider the 9 inch).
For Mopar it's easy, if you are making power go with the 8.75, if you are making big power go with the Dana.

BTW, it isn't that much heavier and if it makes you feel better, think of it as adding ballast over the rear wheels for traction.
How much heavier are they Neil, 40 pounds?

[Chryco Psycho]

I think Hot rod did a test using a Dana & an 8 3/4 in a dart at the dragsrtip the results were almost no difference , the Dana slowed the car by a few hundredths of a second , but the car was easier to launch with the extra weight on the wheels  , I forget exactly what the weight difference was

[Blown70]

are danas good for racing? i heard that they are really heavy and mostly used for 4x4

I have a nice narrowed dana in My 70 However,  the car spends most of its days on jack stands

[Steve P.]

I think Hot rod did a test using a Dana & an 8 3/4 in a dart at the dragsrtip the results were almost no difference , the Dana slowed the car by a few hundredths of a second , but the car was easier to launch with the extra weight on the wheels  , I forget exactly what the weight difference was

You beat me to it Neil. That was a pretty good article. I bought a truck Dana with a power-lok and 3.54 gears for $80.00 on Craigslist.

If you are going to a junk yard for a DANA, try to find one that has equal length tubes. My buddy bought one for $250.oo, (he's pissed at me for my find), and had to cut out and replace one tube. The tube was kind of expensive as it has to be seamless. (He's really pissed at me)!!     Hehehehehee......

Sorry Scotty...

[deputycrawford]

I have heard that Dana's are 200 lbs. heavier. That explains the slower times. 100 lbs is a tenth. That's about right. The strength difference is awsome. Go for the Dana or the 8 3/4. Might as well stick with Chrysler stuff and get all your parts out of one camp.

[THMPN73]

thanks alot guys...
i havent come across too many 8-3/4 yet but ive got all winter to find one

[Steve P.]

Why not post a WANTED in our classsssssified section??

[Rocky]

I think Hot rod did a test using a Dana & an 8 3/4 in a dart at the dragstrip the results were almost no difference , the Dana slowed the car by a few hundredths of a second , but the car was easier to launch with the extra weight on the wheels  , I forget exactly what the weight difference was

I seem to remember the same article saying that the Dana was 150# heavier.  The conclusion was that for most cars, the difference was a wash.  The only reason to buy a Dana is if you are breaking your 8 3/4.

[Chryco Psycho]

& I do regularly break 8 3/4 diffs 

[Mike DC]

 
I don't think the weight penalty is all that bad.  Maybe 40 or 50 pounds, but not hundreds.

There was an old "Hot Rod" article about the Dana 60 versus the Mopar 8.75" rear.  (I think it was for the old Stage V Hemi A-body that they did during the 1990s.)
They found that the Dana 60 was about 250 pounds, and the Mopar rear was about 205 or 210.  That's not so much different.


I think the Dana 60's boat-anchor reputation comes from the 4x4 community.  They talk about Dana 60s being so heavy, but that's for a different axle setup for the most part.  Their axle assemblies can include huge hubs, huge brakes, larger suspension mounting brackets, front steering parts, etc.

 

[Rocky]

Back to the origional question, I believe that building a quality Ford 9" would take more time, effort and money than it would take to swap in a comperable 8 3/4" unit.

[deputycrawford]

Rocky, I agree with you. An 8 3/4 unit is about exactly the same strength and can be found with all the suspension mounting already attached in the right place. The extra money you will spend at the purchase of the housing, you will not spend for the fabrication of the unit. It should be ready to bolt in.