1968 Dodge Dart Driveshaft

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Peacefulbob

Peacefulbob

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Hello,
I am looking for the measurements for, or someone that might have and want to sell, a driveshaft for a 1968 Dart with a 904 transmission and 8.75 rear axle. What is the overall length? Any information would be appreciated.

Thanks.
 
We need more info, like what size u joints, and so forth. We can't see it from our house. LOL
 
If you have a drive haft yoke, slide it in until out bottoms out, pull out about 3/4"-1" an measure yoke to yoke on center best you can. If your working with a drive shaft shop ask them.

Was an 8-3/4 ever offered with a 904? Seems like if someone ordered a heavy duty rear end they would have got a 727.
 
My 68 273/904 combination had an 8 3/4 rear end, I got it from the original owner (my grandmother) when she bought a 72 Satellite Sebring Plus in 1972.
 
The measurements are well known and included in Galen's White Books on Mopars. I am at the Holley Moparty or I would simply look it up and tell you the proper length, u-joint size doesn't matter. If someone has a copy hanging around just look up the correct size...
 
I don't believe that this combination came from the factory. A 904 was not with a 8.75 in 68 dart. I could add 4 inches to a 727 with 8.75 combination i guess?
 
It's all right there in the factory parts book...

Screenshot_20240913-125439.png
Screenshot_20240913-125533.png


So yes the 8-3/4 came with the 904 And the 3 &4 speed manual.


68 might be different but it's all in there
 
I really appreciate all the information. This has been great to get so much response so quickly. Thanks a bunch to everyone!
 
HemiSSDart said:
The measurements are well known and included in Galen's White Books on Mopars. I am at the Holley Moparty or I would simply look it up and tell you the proper length, u-joint size doesn't matter. If someone has a copy hanging around just look up the correct size...
Click to expand...
Good info. Thanks. Also thanks to Dana67Dart. So the correct length for a 68 with a904 and 8 /3/4" is 52.58"
 
1968 Dart 270 said:
So the correct length for a 68 with a904 and 8 /3/4" is 52.58
Click to expand...
That may or may not be correct.

Did you look in the 68 parts book?

If the parts book says so, it is probably going to be correct, BUT....

Measure twice cut once
 
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Dana67Dart said:
That may or may not be correct.

Did you look in the 68 parts book?

If the parts book says so, it is probably going to be correct, BUT....

Measure twice cut once
Click to expand...
Thanks for sharing your parts book with us
As far as I know nothing changed. Four or 5 other members contacted me saying 52" was correct,and in many old threads others had said 52" as well. I've also had a couple folks in my wanted to buy post for the driveshaft say and show with photos that your book is correct. One member has both 67 and 74 dart driveshafts removed from 904 trans cars with 8 3/4" rear ends..same thing 52" so it would appear your 67 book is right and applies to my 68 dart and later models
Maybe someone here with a 68 parts book will chime in. Youre right about measuring twice,but hopefully im not cutting my driveshaft though. The goal is to buy one that's factory made and correct and not mess with mine.
 
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My current driveshaft is 52 3/4. I’m not sure if that is ok or I should cut it down to 52. It has a vibration so I am definitely going to have the balance checked out.
 
This is from the 68 parts book. Even though it’s commonly agreed upon that the 833 and 904 are the same length.. the book shows two different lengths for the drive shaft with a 8 3/4. Maybe the .75 difference isnt enough to be detrimental ?

IMG_9892.jpeg
 
FlamesAreWicked said:
That’s the U joint. The 7260 is for your lighter duty 225 or 318 models typically and the 7290 is for the more performance oriented models such as the 340 and 383
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Bingo. That's what I was assuming when I saw the numbers but wasn't sure. But if you look at the book again the 51.53" measurements are also A833 transmissions. The a904 only has one ujoint size listed 2760 and shows the same number as before 52.25."
 
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I skimmed this thread and will tell you that I chased driveshaft vibrations in my Duster last year because I guessed the right length based on “factory spec length” and what I measured while car was on a 2 post lift and was WRONG. Wrong cost me several weeks of enjoyment and $800 because I decided to call an expert (Strange Engineering) and they told me how to measure it. They built a new driveshaft for me and it was 3/8” longer than what I took out (cap to cap) and my violent driveshaft vibration was gone.

You need to measure with the car’s weight on the suspension and never forget facts like +2” leaf springs and pinion angle shims to fix pinion angle will affect your driveshaft length. Even if the car is built to factory spec it does not mean it takes a factory length driveshaft, mine is 1/4” longer than posted factory spec due to “other variables.” Measure every time…

Strange Engineering treated me well, I knew it would be expensive, but I knew they are among the best in custom length Mopar driveshafts. And being mid summer I wanted to obtain the correct length driveshaft and soonest possible, and Strange Engineering hooked me up. Shortest lead time and knowledgeable techs you can actually talk to on the phone.

You can go where you want but know that too long risks broken transmission and too short is not fun vibrations (scary) on the highway with 3.91 gears at even 60 mph. So measure correctly and buy once, I measured wrong and bought twice.
 
Wvbuzzmaster said:
I skimmed this thread and will tell you that I chased driveshaft vibrations in my Duster last year because I guessed the right length based on “factory spec length” and what I measured while car was on a 2 post lift and was WRONG. Wrong cost me several weeks of enjoyment and $800 because I decided to call an expert (Strange Engineering) and they told me how to measure it. They built a new driveshaft for me and it was 3/8” longer than what I took out (cap to cap) and my violent driveshaft vibration was gone.

You need to measure with the car’s weight on the suspension and never forget facts like +2” leaf springs and pinion angle shims to fix pinion angle will affect your driveshaft length. Even if the car is built to factory spec it does not mean it takes a factory length driveshaft, mine is 1/4” longer than posted factory spec due to “other variables.” Measure every time…

Strange Engineering treated me well, I knew it would be expensive, but I knew they are among the best in custom length Mopar driveshafts. And being mid summer I wanted to obtain the correct length driveshaft and soonest possible, and Strange Engineering hooked me up. Shortest lead time and knowledgeable techs you can actually talk to on the phone.

You can go where you want but know that too long risks broken transmission and too short is not fun vibrations (scary) on the highway with 3.91 gears at even 60 mph. So measure correctly and buy once, I measured wrong and bought twice.
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Man! That sounds like an expensive headache. this is exactly why I'd rather pay to buy the correct factory original driveshaft that Chrysler made to fit the car then play around measuring things and trusting a shop to cut my 7 1/4" driveshaft to the correct length and for it to work after. It's also cheaper to buy a factory driveshaft that someone took out of a stock car with an a904 and 8 3/4". Chrysler engineered and manufactured the part and it obviously worked in the sane car with the same setup.
 
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1968 Dart 270 said:
Man! That sounds like an expensive headache. this is exactly why I'd rather pay to buy the correct factory original driveshaft that Chrysler made to fit the car then play around measuring things and trusting a shop to cut my 7 1/4" driveshaft to the correct length and for it to work after. It's also cheaper to buy a factory driveshaft that someone took out of a stock car with an a904 and 8 3/4". Chrysler engineered and manufactured the part and it obviously worked in the sane car with the same setup.
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I was thinking about going that route for round 2 after round one I went too short, but had I done that I still would have been too short. Granted I have +2 leafs and the pinion angle shims shoved the axle back a little too so it was bound to be different, but had not learned that yet. But I am using a V8 on conversion mounts on a slant 6 K frame so getting a factory shaft length for application may or may not have worked with or without my other variables… So glad I didn’t do that used factory spec shaft route, I would have wound up buying THREE times instead of TWO…

Which headache do YOU prefer, learning how to measure proper to get a proper length shaft on one try or randomly buy used shafts and hope you are lucky enough not to have a vibration… because if vibration… you have to measure proper anyway and then buy again…
 
Wvbuzzmaster said:
I was thinking about going that route for round 2 after round one I went too short, but had I done that I still would have been too short. Granted I have +2 leafs and the pinion angle shims shoved the axle back a little too so it was bound to be different, but had not learned that yet. But I am using a V8 on conversion mounts on a slant 6 K frame so getting a factory shaft length for application may or may not have worked with or without my other variables… So glad I didn’t do that used factory spec shaft route, I would have wound up buying THREE times instead of TWO…

Which headache do YOU prefer, learning how to measure proper to get a proper length shaft on one try or randomly buy used shafts and hope you are lucky enough not to have a vibration… because if vibration… you have to measure proper anyway and then buy again…
Click to expand...
I know what you mean. It seems like it's always something. Hope you get it sorted out so you can start enjoying your car again.
 
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