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Anyone ever had a driveshaft shortened...
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Author:  bmimken [ Sun Jul 06, 2008 3:43 pm ]
Post subject:  Anyone ever had a driveshaft shortened...
I am in the middle of thrashing on the Duster and swapped out the 7.25 rearend for a 8.75 rearend. I obviously have to shorten the driveshaft, but was wondering if anyone else who has done this remembers how much they had to? I am trying to compare my measurements with someone else's.

Thanks, Brian
Author:  Slant Cecil [ Sun Jul 06, 2008 4:12 pm ]
Post subject: 
I went from a 8.25 to a 8.75 in my '84 D100. Shortened it 1.25". I think the difference between 7.25 and 8.75 is 1.75". Cost to have it shortened, balanced and 2 new U joints was $120.
Author:  bmimken [ Sun Jul 06, 2008 5:20 pm ]
Post subject: 
Thanks Cecil, I measured just over 2 inches but that was with the slip yoke all the way in. Does anyone know how much freeplay I am supposed to have?

Thanks, Brian
Author:  Joshie225 [ Sun Jul 06, 2008 5:41 pm ]
Post subject: 
7 1/4 to 8 3/4 needs a 2 1/4" shorter driveshaft.

Image
Author:  bmimken [ Sun Jul 06, 2008 6:12 pm ]
Post subject: 
Thanks Joshie225, I've been paging through my factory service manual and couldn't find the info.

This forum ROCKS, so glad I found it a couple years ago.

Thanks, Brian
Author:  slantzilla [ Sun Jul 06, 2008 7:22 pm ]
Post subject: 
I've done the swap 3 times. 1.75" is the magic number for me. :shock:
Author:  Dart270 [ Mon Jul 07, 2008 5:15 am ]
Post subject: 
I have used 2". I think Triangle Driveshaft is pretty close to you and does good work. Make sure he balances it too.

Lou
Author:  Andy's GT [ Mon Jul 07, 2008 8:00 am ]
Post subject: 
oh, you want to do it right....
we cut down the one from a 73 dart to convert dads a100(only for around the yard) by cutting where we guestimated by holding it up, then wrapped duct tape around the inner piece so it was at thick as the inside of the outer piece, then had a buddy weld it up, yeah, its a little rough...but it moves haha, good luck with the swap, sounds like youve got the info you need!
Author:  bmimken [ Mon Jul 07, 2008 8:48 am ]
Post subject: 
Thanks for the info Zilla and Lou. Can you guys tell me if your swaps were done on '67-later or '66-earlier A bodies? Or both?

Lou, Triangle driveshaft was the place I had planned on using (per your recommendation at the banquet).

I am going to re-measure (again) to check myself one last time. Sounds like I need to be around the 1.75"-2" range. I measured almost 2.175" on mine.

The 2.25" measurement seems like a lot, I wonder if the 8.75 rearend came with a 727 tranny? Is the 727 same length as the 904? I'm probably overthinking this whole thing.

Thanks, Brian
Author:  slantzilla [ Mon Jul 07, 2008 9:48 am ]
Post subject: 
I did the swap on my '76 Duster, '66 Valiant, and a '70 Swinger. All were 904/7.25" to start. I actually have the shaft out of the Duster in the Valiant now. :shock:

A 727 is approximately 4" longer than a 904.
Author:  bmimken [ Mon Jul 07, 2008 10:45 am ]
Post subject: 
Thanks Zilla, I guess that clears up any question of different driveshaft lengths between the early and late A bodies.

Thanks, Brian
Author:  Shaker223 [ Mon Jul 07, 2008 10:47 am ]
Post subject: 
7.25 to 8.75 swap....I shortened it 2". $40 to cut and reweld
Author:  bmimken [ Sun Jul 13, 2008 8:40 am ]
Post subject: 
Update...

I ended up going with shortening the driveshaft 1 7/8". Had it rebalanced and new ujoints installed. Fits real nice, but have not driven it yet. I am still working on the rear brakes. Cost me $160 for everything. Thanks for all the responses! :D

Brian
Author:  70valiant [ Sun Jul 13, 2008 5:00 pm ]
Post subject: 
Cut 2 1/4" off, ballanced, new joints, $110 here for the 7 1/4 to 8 3/4 swap.
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