Changing rear ends but also driveshafts?

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Drache

Drache

1971 Dodge Dart Swinger
Joined
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Now someone informed me that changing from a 7 1/4 rear end to an 8 3/4 means my drive shaft will no longer work and would need to be shortened and rebalanced or buy a new driveshaft.

Now I know there are no companies locally that can shorten and balance a driveshaft. So shipping one is going to cost me a good chunk of change.

At the same time so is buying one. But if I do buy one how do I know which one to buy?
 
I would think the determining factor would be "how much power" you have in 'er and so whether it's a good idea to upgrade to the larger series U joints, -- what does the 8 3/4 have for a yoke?

NObody in a town that size runs a machine shop? Sounds to me like a road trip to Prince George is in order.
 
67Dart273 said:
I would think the determining factor would be "how much power" you have in 'er and so whether it's a good idea to upgrade to the larger series U joints, -- what does the 8 3/4 have for a yoke?

NObody in a town that size runs a machine shop? Sounds to me like a road trip to Prince George is in order.
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The 8 3/4 rear is bare bones, no gears or anything else. I have to pick up all of that.

3271h0220.jpg


As for power Ive never had her on a dyno. She has some pick me up though so I know she's not a plain stock 318.
 
You think the driveshaft work will be pricey.....wait till you start gathering all of the rest of the parts for your 8 3/4 housing! The difference in length of the driveshaft between the 7 1/4 and the 8 3/4 is about 2 3/8". I'd look at where the seal is running on your yoke now and add or subtract as necessary to correct any current length problems. You need about 1- 1 1/4" of travel before the yoke bottoms out against the seal.
 
Yep, depends on what u-joint yokes are there/changed. Here in North Fl, 20 miles, new custom driveshaft with joints, new yoke, $230. None up there?
 
just saw someone offering hp moly drive shafts complete online I'll try to remember where they started at 250 or so and went up depending on the yoke and u-joints you want they know what you need length wise you just tell them the car and the setup and they go from there .

It might have been mancinis, try there
 
Before you spend any cash on a drive shaft you have to do the following:

Build the rear end and set it in the car with the springs your are planning to run and the weight on all 4 - wheels.

The yokes on the output shaft of the tranny and rear end, make them take the same size u-joint for balance issues.

Measure the shaft that fits YOUR car, there are production tolerences and the shaft in mine ended up 3/8" longer than the factory recommended shaft length with new springs.
 
cannucky said:
just saw someone offering hp moly drive shafts complete online I'll try to remember where they started at 250 or so and went up depending on the yoke and u-joints you want they know what you need length wise you just tell them the car and the setup and they go from there .

It might have been mancinis, try there
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I find it impossible to do a moly shaft for 250, with a slip yoke ? it would all be china material, which doesn't mean you aren't getting all china material anyway at a big well known advertized shop.

better off with a stock shaft.
 
upgraded mine to a 1350 ujoint with a new yoke and driveshaft from Mancini racing. The new yoke was around $100 shipped and the shaft came to about $400 with shipping. Everything works very well in a 12 second race car.

bob
 
Have you looked for Semi repair shops, or off road shops in your area??
They may seem unlikely for a car, but if they have a machine shop, they may be able to do it.
 
73swinger said:
Have you looked for Semi repair shops, or off road shops in your area??
They may seem unlikely for a car, but if they have a machine shop, they may be able to do it.
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Yes, look for driveline shops for the heavy trucks. Or stop in at a truck stop or fleet maintenance garage and they'll have a source for shafts. I also agree with Super - No need for anything special.
 
cannucky said:
wouldn't be the first time the price in the print add wasn't up to date eh .
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Or it may be up to date with lesser wanted materials and its not specified. . . .your jaw would drop, hit the floor and get stepped on if you knew some of the big name shops partaking in junk. . . .
 
Supershafts said:
Or it may be up to date with lesser wanted materials and its not specified. . . .your jaw would drop, hit the floor and get stepped on if you knew some of the big name shops partaking in junk. . . .
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no it wouldn't actually , I have been screwed and tattooed as they say many times during my own restoration and have become leery to the point of questioning everything before I buy .I was just suggesting to the OP that there were options out there but buyer beware is a given these day's eh!
 
The local heavy truck shop built my last drive shaft this spring.
New spicer ends with a 3.5" dia shaft and they installed new spicer u-joints.
They used my old trans yoke.
Total bill for a ready to bolt in balanced drive shaft was $260.00
Runs smooth no issues.
 
cannucky said:
no it wouldn't actually , I have been screwed and tattooed as they say many times during my own restoration and have become leery to the point of questioning everything before I buy .I was just suggesting to the OP that there were options out there but buyer beware is a given these day's eh!
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So if i told you jerry bickle race cars was using china junk you wouldn't be surprised.

if its based on price its not worth suggesting, screwed to tattooed and suggesting based on price....
 
as I said No I wouldn't be surprised , disappointed if I had spent my money there and gotten hosed , the OP was alluding to cost being a factor , would it surprise you to find out prices on some things vary wildly depending on local or volume of business ? would it surprise you that I was only offering a little input to the OP not posting to bicker with you ?
have a nice day eh -thanks for coming out

ps Drache where are we at with the signature board ?
 
Not bickering, making it crystal clear, the variances between (business taxed to hell NY) here and other states if its done right aren't hundreds difference, unless its china.

Se beware when you see the gentlemen above with 260 without a slip and someone tells you 260 for the entire thing...
 
So who are some good companies to get quality work for an affordable price? What kind of range on a new Driveshaft?
 
Try your local truck shop ask if they have a balancing machine (if they are a WD for spicer and cert for SPL shafts they have a balancing machine) then just ask them to build it all spicer parts. . .

As for who isn't going to try and sneak some china in......some mentioned in this thread will. . .


. If you have a local shop see them and tell them no china ****, if not call whoever and tell them the same thing. . . (that means no neapco parts either they are a china WD with neapco boxes) It's all spicer parts or all Aluminum and then there are only 3 companies making non china parts for AL shafts which if i were you id do AL over stl all day. . .. many added benefits
 
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