Drive shaft length specs

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I'll just say... be careful....

That's another one that someone REALLY needs to look it over because there's some bad info in it. Been up at moparts for a few years.
 
crackedback said:
I'll just say... be careful....

That's another one that someone REALLY needs to look it over because there's some bad info in it. Been up at moparts for a few years.
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You are correct. I can guarantee the spec on the 68 Barracuda with a 727 and 8-3/4 rear is wrong. It shows a longer driveshaft (albeit by only a couple tenths) with a 727 trans. and 8-3/4 than it shows with a 904 trans. Should be 3 to 3-1/2" shorter with a 727
 
i have wondered what the correct driveshaft length is supposed to be in my car.

68 dart ....it had a 904 and 7 1/4

i recently changed it to an 833 OD with the same rear end and i used the same driveshaft but changed to slip yoke ....it runs and drives but i think it looks to "tight" not much slip yoke visable when not in motion and when removing the driveshaft ...it takes a little jimmying to get it out. :happy1:
 
I like getting new shafts made for my cars and trucks after tweaking suspensions and doing tranny and other driveline swaps / work. Those variables put the only truly correct answer on the tape measure in your hand. Best length gives minimal slip yoke clearance of about 1/4 to a 1/2 inch at full droop.
 
I know this is an old post . but after looking at it I was just wondering what a Dana 60 in a 71 dart with a 904 length is ??? I guess I will find out when I have on build for it.
 
Just opened up my browser, and went to forabodiesonly to post a question thread. I didn't even get a chance, because you answered it. The other forums don't have resident psychics. Thank you so much for the post. By the way, what's the weather for the next week ? any choice numbers for lottery predictions ?
 
So theoretically, if I have 1975 slant 6 duster, 904 w/ a 7 1/4, and I have a 1969 barracuda 340 727 w/ a 8 3/4, and I want the 69 drive train in the 75. I can swap the drive shaft, and rear into the duster first. Allowing me to drive that slant 6 / 904 combo, until I'm ready to do the engine, and trans, and all the parts will work properly.
 
garyfish340 said:
So theoretically, if I have 1975 slant 6 duster, 904 w/ a 7 1/4, and I have a 1969 barracuda 340 727 w/ a 8 3/4, and I want the 69 drive train in the 75. I can swap the drive shaft, and rear into the duster first. Allowing me to drive that slant 6 / 904 combo, until I'm ready to do the engine, and trans, and all the parts will work properly.
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The yoke for a 904 trans. is different than a 727 so it won't be a direct swap. It'd surprise me if the driveshaft length is correct also. A 904 is about 3" shorter than a 727 and a 8-3/4 is longer (yoke to axle centerline) than a 7-1/4... You'd have to be real lucky for the driveshaft to be the right length.
 
I like what fishy68 said, and his info. I have a D.S. from a 727/8.75 combo that I drove for years, and I have another combo from a 904/7.25 that ran really smooth. So I should forget the yoke, and measure the shaft lengths. I will say though the 904/7.25 combo is much smaller in diameter, and tapered. So the one shaft is beefy, while the other has a taper, which theoretically should make it strong too.
I hate theoretics...
 
Earlier this year I needed to shorten my driveshaft after putting in an 8.75 to replace the noisy 7.25. I did some measuring and decided it needed to be shortened about 2".

While looking through my factory shop manual I discovered they had the driveshaft dimensions listed for all the various transmission/axle combinations. The book confirmed my measurements and said that it needed to be cut just a fraction over 2". It was actually listed in thousands, not fractions, but I don't remember the actual number right now.

So check out your OE shop manual. It just might have the info you're looking for.
 
This would be a perfect time and place to start our own verification of that list. Everybody should list their combo and car and give the center to center driveshaft measurement.
 
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