8 3/4 Rearend Question

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ramcharger

ramcharger

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I've got a line on 8 3/4 rear end out of a '79 Dodge truck with 3.55's and a sure grip for a great price. Can this be modified to fit under my '72 Duster?

i'm not scared of any fabrication and figured I'd move the springs in anyway. How big of a hassle is it to shorten the rear end and what measuments would be correct for the above Duster? Would I be better off farming out the shortening work to someone with a jig?

Thanks all!
 
I can't see why you can't make it work. I do think you'd be better off farming it out to someone with a jig so the ends get put on exactly straight. Anybody can put them on but even the best of us can probably only get them within .100 which would probably eat the bearings out. Maybe even do more damage. The width from axle to axle is 55.6" and the spring perches are 43.0" apart. The perches shouldn't be any problem for you to do though. You'd also need axles unless you already have them. The Yukon axles are a nice upgrade and the price isn't too bad. By the time you find stock axles and have them cut down and resplined and hardened you'd probably have 3/4 as much as the new Yukon's cost.

Here's a page that has a ton of info on the 8-3/4. It will probably answer any other question you have.

http://www.moparts.com/Tech/Archive/axle/21.html
 
yeah they can be modified but i agree with fishy 68 let someone with a jig do it for you but if you can get it for a good price and it has 3.55s and a sure grip you should jump on it keep in mind the center section alone is worth450.00+ so if you got a good price lined up you could even just use that but if you plan on mini tubbing etc you could just have the truck one cut down and go from there. I think also you will need the axles like fishy said and i think you also need different brakes to fit the a body bolt pattern. Good Luck Justin
 
Thanks Fishy and jjr,

You guys are right, I'll farm out the shortening work. Last thing I want is to be burning bearings or breaking an axle housing at the strip. Aftermarket axles and brakes are in the plans too. Thanks for the link too Fishy, I'll read up on this.

I was removing some front fenders and a roll bar from a parts Ramcharger when the guy asked me if I ever heard of an 8 3/4" rear in a Ramcharger. I said "It's possible", he said "Check it out, if it is a 8 3/4" you can have it for $100". Needless to say, I asked him to hold it for me. I thought I would check here first and make sure I could it use before removing it from the truck.
 
If it's the stock rearend, it won't be a 8 3/4. I think they stopped using those rears in the early 70's. I could be wrong though.
 
It's in a '79 and it is definitely an 8 3/4. I have no idea wether or not it's factory stock though.
 
ramcharger said:
It's in a '79 and it is definitely an 8 3/4. I have no idea wether or not it's factory stock though.
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If i remeber right the 8.75 rear was ended in 74 or 75, but someone could have put this rear in a 79 ramcharger. Ive seen 8.75's in cars that shouldnt have been in, usually rears go out and just get replaced with an earlier 8.75
 
thanson_mopar said:
If i remeber right the 8.75 rear was ended in 74 or 75, but someone could have put this rear in a 79 ramcharger. Ive seen 8.75's in cars that shouldnt have been in, usually rears go out and just get replaced with an earlier 8.75
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Very possible! Most truck guys I know would try to find a Dana 60, but an 8 3/4 would work just fine if was readily availible at the time.
 
Yeah that was a screamin deal!! Probably not original like the others said but it doesn't matter. Any 8-3/4 with 3.55 gears and sure grip is worth alot more than that.

If you really wanted to know out what it came out of you could compare dimensions with those shown on the Moparts link and probably figure out what it came out of.
 
I snagged it last weekend, here it is complete with leaky axle seals at no extra charge!

Rear end.JPG
 
fishy68 said:
And you didn't go by the local car wash on the way home?? tisk tisk:-D
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lol! I had to rent a flatbed from the local home improvement store to pick up this rear for the Duster and a door and top for the Ramcharger and they charge by the hour. NOW IF MY STUPID RAMCHARGER WAS DONE, this wouldn't have been a problem, lol! :-D I was in such hurry to grab this stuff that I just torched out the u-bolts, brake line, shocks and driveshaft as it was a 120 mile round trip.

In retrospect, if I was smart, i would have grabbed the driveshaft too instead of torching it. :angry7:
 
Might be cheaper to buy a 8.75 a rear and axles install the 3.55 chunk and then sell the leftovers. Some of the 8.75 axles cant be cut and resplined due to being tapered. But someone looking at a tub job could use your old housing.
 
daredevil said:
Might be cheaper to buy a 8.75 a rear and axles install the 3.55 chunk and then sell the leftovers. Some of the 8.75 axles cant be cut and resplined due to being tapered. But someone looking at a tub job could use your old housing.
Click to expand...

You have a good point Daredevil. I had planned on buying new aftermarket axles anyway and am presently looking into a price on having the housing narrowed. If having the housing narrowed is more expensive than an "A" housing, I'll just sell it. Thank you for the advice!

I might add that I'm having some difficulty in finding someone here in Colorado that is capable of performing this work and doing it right.
 
I got a quote of $310 to narrow this rearend, does this sound reasonable? This is supposed to be a nationaly known and very reputable shop.
 
I have seen cases go for 300 that are for a bodies ...i am looking for a complete one my self
 
Thanks! I'll keep my eyes open. I did see a a-body 8 3/4 489 case with 3.23 and a sure grip locally for $450. Supposedly has a bad ring and pinion. I may be moving into a new house (waiting on appraisal) shortly so I can't swing it, otherwise I would get it, and have a sure grip for the street with 3.55's, and a spool for the strip with 4.11's.
 
I would check with Moser engineering I talked to them about doing one for me and the cost to narrow the housing and re-spline my C body axles was under 300. I don't think that included spring perches and shipping was on top. If you shorten your own housing or have it done you can set the width to use the standard 10 or 11 brakes and will be big bolt pattern with no changes.
 
Thanks furz4! I'll check with Moser too. I had planned on buying new axles anyway since this car will be raced, so I won't need the axles resplined.
 
Has anybody here actually MEASURED the width of a stock A body 8 3/4" housing? I have a chart that says it's 51.4" wide & I'm wondering if anybody can verify that dimension. I have a guy who is going to build me a narrowed housing & I know how much narrower I need than what I have now but I'd like to be sure of the width of the stock 71 A body 8 3/4 rear I have. I can't get an accurate measurement of mine without pulling the pig & the backing plates & once I do that it makes the car really hard to move around until I put it back together. I'm trying to save myself a few steps.:-D Thanks for any help you guys can give.
 
Fishy says it's 55.6" from axle to axle, which I take to mean axle flange to axle flange.
 
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