Rear end to long for my duster?

[6 packin]

I currently have a 73 Duster which has a 8 1/4 rear in it! I have a sure grip and a 8 3/4 rerar from a c body! According to my Mopar chassis book there is 5 inches diff between the two. Thats only 2.5 inches per side! Looking at my Duster they seem to have to narrow a rear from the factory! Will this thing bolt up and run with no major problems? Of coarse I will have to relocate the spring perches. I dont plan to run a real wide tire maybe a 60 series at the most. Will this combo work or am I going to waste alot of time? Thanks for any input or experiance!

[Doug Wilson]

It won't clear any size tire, even though it will bolt up. Even with custom offset wheels - lots of backside spacing, you won't get a desireable result - even with the rel'd springs. Try the "Tire and Wheel" thread on this forum for more info.

[Doug Wilson]

That should read "relo'd springs"

[rainydazes]

i agree with doug your wasting your time. Just finding an A-body 8 3/4 will be very tough. Whats wrong with the 8 1/4 thats the next best thing to a 8 3/4, and you can get a sure-grip for the 8 1/4.

[Tarrbabe]

You will have to also shorten drive shaft with the 8 3/4 as the nose is longer than the 8 1/4.

[dirty dan]

You are going the wrong way with the c body rear. Don`t put your $$$ in an 8 1/4 it wont take the load like the 8 3/4 will. If you go looking for an a body rear you will have a lot of looking to do. find a B body rear they work well in the dusters. It was been some time back since haveing done this . But if memory servs me .I don`t think I even had to move the spring perches. Happy trails.

[dusta340]

i am have the same problem if any one nows if a b-body rearend will work cuz a body 8.75 are to hard to find and i am a 17 year old mopar freek w/ a 72 duster and b-body rears are a dime a dozzen and fit my budjet more so if any one nows let me now i allso have a 340 blocke and crank and rods for sale cheep im in ohio around madina or trade? i need a body parts my email is haneyjr340@hotmail.com

[5th_Ave_Sleeper]

I went through the same thing with my 5th Ave. except I installed a 8 1/4 from a van. Yes the axle is a bit wider, andyes the perches needed to be moved in due to the width diff. Problem was there was no way the wheels would fit under the car. the only solution I could afford was to weld the perches on top of the axle. Getting one narrowed aroun here is expensive. It sits about 3" higher in the rear now, but really doesnt look that bad. some people think that style went out in the early 70's but Im not big into doing what everyone else is doing.
Get some "U" bolts and do a trial run with the sprigs on top. you may like it. if not, your only out a little effort.
Remember measure twice, weld once
Im putting the engine in this weekend and will take a bunch of pics, rear end included.
5th

[jimmycarter]

you could just get the ends cut off and new ones welded on, 6 packin. kind of gives you an excuse to shorten it. youd also need to respline the axles or find others

[dirty dan]

cutting the axels and the banjo . You can do that . But you should know what you are getting into before you try it. Such things as axel length,axel diamiter, weather or not the hardened steel will be removed by re splining and a host of other pertinent facts that will determine sucsess or part failuer. its pretty much dont try this at home or alone. not the first time any way.Happy trails.

[Doug Wilson]

B-body 8 3/4 won't work right either.

[Mills]

B-body unit will work better then C as it is shorter, but you still need to move spring perches and have some custom rims made for offset req'd.

[The Dartman]

I have not seen the C body rear in an A body, but I have seen a B body rear in an A body. The car was a 1969 Dart, and the largest tires he could get on it were about a 8 inch wide 70 series tire. He later bought offset rims to make larger tires fit, but the point is it can be done.

The 8 1/4 rearend is pretty much a joke. I had a race prepped 3.55 geared sure grip setup in my '73 Dart sport that was designed to run low 12's. It broke after 8 months of moderate street driving. I used Moser engineering's resplined axles ($145 back in about 92) in a A body housing and my existing 8 1/4 brakes as a direct replacement. I ran for over 10 years on this setup, running a best of 12.87 with absolutly no rearend problems. I went from a 3.23 to a 3.91 and finally ended up retiring the ol' girl with a 4.30 gear in it. Moser also has "stronger than stock" axles that I recently got for $400 a pair with green bearings and extended studs.

There is also no noticible differnce between the "snout" an 8 1/4 and 8 3/4 that I'm aware of, so I would'nt get too excited about getting a new driveshaft just yet. I've swapped 8 1/4's rearends out of my Dart Sport and my new Duster and it should be a direct replacement. Now as far as the 7 1/4 goes, there's no telling what kind of toothpick Chrysler came up with for a drive shaft, so I can't verify the snout length on that POS.

Dartman

[Doug Wilson]

It will go under there, but it won't work right.

[George G. Leverette]

All C-body axles are not the same, neither are the B-bodies, if you have a C-body 8 3\4 with 28" of axle before the taper thay can be shortened and resplined by a competent machine shop. The housing can also be shortened to a 55.56 track with 43" perches. B-body rear axle dimensions are 59.20" track with 44" perches from 62-70 from 71- 79 the rears measured 53.40" track with 47.3" perches. The best approach would be gears and sure grip for the 8 1\4.

[Doug Wilson]

Unless you've done the B-body rear into an A-body, you can't believe what a losing proposition it is. Forget it and do what George says.

[pro-street dart]

If your considering spending the money to have a axle shortened and with all the other expenses that goes along with that - do it right - go dana. You won't be sorry.

[Doug Wilson]

I think that the Dana setup runs about $2500 - without any kind of brakes, but it sure is worth it if you've got the money.

[dirty dan]

doug there are a lot more people who don`t have the money, as you put it. Then there are people who do. The off set wheels are a lot cheaper then a dana. I think for a street car the 8 3/4 is the way to go. No real need for the heavy artillary. Moveing the pirches is no big deal. Infact I belive mopar perf; sells new ones. I know Mr gasket does. If your engine is making more power then it came with I wouldn`t wast the $$ on a 8 1/4 . Chances are your engine will out grow it. Happy trails

[Doug Wilson]

When you are dealing with wheels having radical backside spacing, you ask for trouble. You can bust axles, lose wheels and blow wheel bearings very quickly. Plus you still don't have enough room for really big tires and wheels.

Our man is much better off with an 8 1/4 that fits, than with a Dana or 8 3/4 that doesn't.

[dusta340]

i am also having the same concers bout my car i got a 8 3/4 from a 74 road runner and i need to now what is it gonna take to put it under my 72 duster what is the measurments on a b body rear compared to a a body and will i need to move perches to make it bolt up im not worried about a real big tire nuthin bgger than a 255 or soso any hep would be great


ps... i aso have a 68 340 short block for sale it needs some work but cranck and rods are good will sell chepp like a couple hundred bucks and also looking for a another 340 or 360 short block fress if possible

[6 packin]

I have droped the c body rear idea, and now I have went with the 66 GTX rear 8 3/4 Which i got from a friend! After moving the purches which was a snap even reused the old ones. Went to slide my axles in oops! ABout 3/4 inch too damn long But did you guys know there is a inchs or so diffrent (shorter) in the early 8 3/4 from 66 and 67 B bodys than the later like 69 Bee's. I didnt I know because I pulled the axles form the bee my self. I was told by a few people that they were shorter, but accoring to the Mopar Chassis Manual 8th edition they are not!. In fact it says that from 62 to 70 they were all the same length. Wrong! There not. Belive me I spent all day today working on it. So I took my bee axles to the machine shop he cut about 1/3 inch off both sides and now im in buisness. Works great! And I have room for 60 series tires. I would say that this swap is fine with me. In fact the 8 3/4 was no heavier than the 8 1/4. As for the dana 60 I would love to have one under my car. But for the money and a 340 Duster I think it would be over kill. and Seems it would take more power to turn the dana, and I know it weighs alot more that the 8 3/4.

[pro-street dart]

This is a dana that I converted from a truck axle, what I'm suggesting is that if you can't find a direct replacement and or your required to have machine shop work done anyway, put the money into a dana, the truck axles can easily be had at a reasonable cost. Your best and cheapest route still is finding a direct replacement 8 3/4" axle.

[dirty dan]

Man I don`t know what kind night mares you have been haveing. But I have never seen off set wheels brake axels or tear up wheel bearings. In fact I have a set of police car rims with 8"of back space added to them. I have been useing them for years on two different cars. Without any adviers efects.