Looking for no BS info on 8 1/4 rears

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Mopardude

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Yea I know the mighty 8 3/4 is the best and that I shouldn't use anything less but I wanna know why I shouldn't use a 8 1/4? I know the 8 1/4 gets ripped on because of the c clips that hold the axels in but can they be beefed up to be a decent axel? My car is around 400hp and is driven street/strip. Right now my car is equipped with the wimpy 7 1/4 and with my engine almost done I am worried about blowing the rear the first time I get up on it. I have been looking around and 8 3/4's are pretty slim around here. Also the 8 1/4 looks like it will work perfectly with my drive shaft with no modifications.

Also whats the deal with Dakota rear ends being swapable with A bodies? I have heard conflicting reports about this. Also are Dakota rear ends considered 8 1/4's?
 
i would like some info too. I heard from a mopar tech that the rears in the Dakota, Jeep cherokee and the like is a 8 1/4 and that the shurgrip units and gears will work if you use everything. I'm gonna run a 8 1/4 out of a 74 318 dart swinger. I wanna find a set of 3:55's with a surgrip eventually.
 
I've never done the dakota swap myself, but I have heard of it too. It is an 8 1/4


As for strength...nothings bullit proof.
8 1/4 FACTs:
1) the 8 1/4 is WAAAAAAY stronger than the 7 1/4 you have,
2)is already a big bolt diff so it is way cheaper to use than an 8 3/4
3)took the pounding of my big block moving a 5500 pound van for about 6 months before I broke the spider gears. Easily repaired. I think the factor there was weight, more than power. It did last longer the 727 in front of it did(2 months)
4)was used by member cuda66273 to run 12's in his a body cuda. REplaced with a dana so he could go 11's

In short, I wouldn't be afraid to use it in the least.
 
the 8 1/4 is pretty strong.... as long as your not running tons of hp and slicks it will be fine...
 
not sure about the dakota rear but certian year sure grips and gears from dakotas will fit the older rears...
 
I'm using an 8-1/4 in my Duster, running low 12s. So far, no major problems.

I'm on my 2nd sure-grip unit, though. The first one was an Auburn, that one lasted like 3 years. The new one is a Dana Spicer.

One of the tubes is starting to twist, I don't think the 8-1/4 is gonna last much longer.

If I had the cash, I'd go with a Strange D60. I think I have a line on an 8-3/4, though, so I may be building one of those over the winter.
 
About the Dakota rear - I'm pretty sure it's not the same 8-1/4 as what came in the older cars. I know that there are different parts for them - go to Mancini and look at the parts available for the 8-1/4, it'll say something like pre-97 and 97-later.

One more thing - nobody makes a spool for an 8-1/4. So if you want a posi-type rear, your only option is a full diff (Auburn, Mopar, Dana)
 
I have been looking at that Strange D60 also. Not sure if I want to pay $1900 for a rear.

Since my car will be drivin on the street also isn't a spool a bad idea anyways?
 
Mopardude said:
I have been looking at that Strange D60 also. Not sure if I want to pay $1900 for a rear.
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Me neither. But you can be damn sure you'd never break it!

Mopardude said:
Since my car will be drivin on the street also isn't a spool a bad idea anyways?
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Yes, that's a bad idea.
 
As far as Dakota swaps go we had a 69 Charger with an 8 1/4 that was open that we bought a posi unit for, but when we went to swap it the bearings were different sized that what the Charger had in it. We had a 94 4x4 Dakota that had an open rear end in it and with the posi sitting in the garage I figured why not try it. I went to put it in and everything worked fine, but the posi unit didn't have the anti-lock trigger wheel (that trips the magnetic sensor installed in the case), so I couldn't get the right backlash setting because even with the posi unit adjusted all the way to one side in the case it was still howling when I drove it. So I guess the moral is that there may bearing issues and possibly trigger wheel issues between the old and new axles (bigger bearings in the new stuff).
 
Dakota axles from 87-91? had 4.5 by 5 lug axles with the same 27 splines, 92-96 the axles were 4.5 by 6 lug with 27 splines, 97-04 the axles were 4.5 by 6 lug with 29 spline axles, 05-? axles are 5 on 5 with 29 splines.

Jeep Cherokee is a better bet unless you find an old Dakota 5 lug axle.
 
LOL this thread sure was dug up by Map63vette huh?

Look at the date, 7-20-04! WOW! Good stuff though
 
Haha, what can I say? I was bored between classes today and looking up a bunch of stuff. Looking at a 67 Dart with an 8 1/4 now, so the topic caught my eye. Probably going to do some swap though, don't think the little axle will stand up well to my heavy right foot =P.
 
There tuffer than what people give them creidt for. Alot depends on what your doing with them. Serious drag racing would be out for any length of time.
 
I've had 4 fail in the last 30 years and they really didn't have a whole lot of power in front of them...They all failed in the same fashon...the caps chattered and the ring and pinion broke ...
I changed the cap bolts on all of them to something 4x better and it still happened.
The very first one I saw I just couldn't believe it happened...It was on a board member here's 68 swinger with a 340 13.0 to one solid 255/265@50Cam Dynamics cam with no tire to really speak of ...just a 70's bias tire.
If you want the NO BS on 8 1/4's ask ifitsgotwheels...he broke one
 
That is typical of how they fail and the simple fix is one of the cast covers with the jack screws that support the caps that you can get from the off road supply houses.
 
I have the 8-1/4 in my 408ci Duster. I drag raced last summer with street tires and it did fine. However I could not get good traction with those tires. I am going to try it with street radial slicks and baby it off the line. It has the 74 or mid 70's axle and I put in an 87 gearset with 3.55 and suregrip. There was issue with carrier bearings being different on OD. Just have to get different bearing set with right OD (two sizes OD with same ID on bearing. I haven't found an 8-3/4 yet either.
 
I know I'm going to get flak for this, but I purchased an a-body 8.75" suregrip with 3.23's, along with a driveline to fit, back in 2001. I purchased it to replace the 7.25" in my Duster. However, I started going to school in 2002 full-time (no time for cars), then I sold the Duster a year later. Still had the rear-end in the backyard until 2006. My folks finally got sick of looking at it, so I took it down to pick n' pull and just dropped it off--no money or anything. Ever since I got my Dart I've been kicking myself for letting such a rare item get away from me. Nobody to blame but myself. I hope at least someone got some good use out of it.
 
abodyjoe said:
the 8 1/4 is pretty strong.... as long as your not running tons of hp and slicks it will be fine...
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i had a 8 1/4 in a scamp had a mild 318 with 360 heads no perf mods other than cam.... i blew that rear to pieces... big bang....lol
 
Holy freaking moly!!! Another resurrection. This thread was originally started nearly 11 yrs. ago!!! That has to be a record by far. I sure hope the OP figured out what he needed since he's had nearly 11 yrs. to do it, lol
 
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