driveshaft question 904 to 727 swap

[edog70]

I changed from a 318 with a 904 to a 440 with a 727 in my 70 Challenger with an 8-3/4 rearend. I found a driveshaft that was 43.6 inches long from eyelet to eyelet, which I thought was correct according to the "Challenger and Barracuda Guide", by Paul Herd.  After sliding the yoke in to the tailshaft, there is still 3-1/4 inches of yoke showing, when the driveshaft is bolted to the rearend, and the wheels on the ground.  This seems too much to me. I have the original driveshaft I can use to make it the correct size, but don't understand why it's too short.  Could the tailshaft from my 727 be shorter than normal?  (it's an aftermarket tranny from TCI, but all of the linkages hooked up okay.)  Has anyone had a similar experience?

Thanks

e   

[ted]

I WOULD BE MORE worried of the crap that TCI builds.

[tactransman]

How much spline engagement length do you have on the output shaft? Is the yoke pretty tight when it is bolted up? Up and down/side to side?

[422STROKER]

I thought that Challenger driveshafts are about 2"'s longer, maybe you got a 'cuda one?

I looked at the Herd info quikly and maybe it is a typo.

If you look at all the other combinations including other BB/SB combos  Chally ones are 2"'s longer.

Tom

http://books.google.com/books?id=-Nq_KTNYEEEC&pg=PA93&lpg=PA93&dq=driveshaft+length+challenger&source=web&ots=HfSGa1VENo&sig=7dYg1PqTXqDp3xARvYjP6un35zU#PPA94,M1

[purple1]

  Some one had installed a Cuda shaft in my car when I got it. Only about 3/4" to 1" of the splines contacted, and a big block car to boot. 

It is about 2" shorter than the Challenger shaft. 

Dave 

[Chryco Psycho]

there should only be 1" or 1.5 of yolk showing , so your shaft is too short [no pun intended]
43.6" sounds right for a Cuda with an 8 3/4 diff

[Got JOB]

Is this the length from the end of the housing or from the end of the boot type oil seal? My '74 challenger has about 3" of the yoke showing but has the flat oil seal in the housing. I also changed from a 904 to a 727.

[tactransman]

I went out and measured my driveshaft ('73 Challenger 8 3/4 rear ) 45 3/4 inches u-joint center to center. 

[purple1]

I went out and measured my driveshaft ('73 Challenger 8 3/4 rear ) 45 3/4 inches u-joint center to center. 

Exactly it, about 2" shorter for a cuda shaft 45.75" - 43.6" = 2.15" or about 2".

Don't run with the wrong one.  Lucky I found (and replaced with the correct length) mine before anything bad happened.

Dave 

[edog70]

I HATE IT WHEN MY SHAFT IS TOO SHORT!!
The length that sticks out is from the edge of the tailshaft, not the seal.  Also, the splines don't start right on the end of the shaft, they are about an inch in, so I bet there is only a couple of inches contacting spline to spline.  I will definitely fix it.
I will have to use the yoke from the shaft I scrounged, and couple it to the original shaft from the 318/904, then have it shortened.  I called around, and it should only cost $75-100.
I kinda figured that wasn't right (the book)....Maybe a letter to the editor is in order.....(HAHA).
Thanks for the help!


e
 

[422STROKER]

Maybe a letter is in order to the editor...

Tom

 

[purple1]

It's only Challenger owners that would ever have this problem with it. 

Dave