Drive Shaft

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66MOPAR77

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I know this prob shouldn't go here. But Early A guys will know this ,
I'm putting in a 360 stock bottom end magnum heads magnum 4 barrel intake, ect, 904 trans with a 8.75 rear end from a 69 B-Body, 489 casing 323 gears with sure grip, I kept the factory drive shaft, will the length fit and what do I need to do to get the the drive shaft u-joints to fit the 489 casing, if the length is good
 
I see it will be too long be cause of the center line to u-joint. And the distance from center line to u-joint is greater on 8.75 we are lookin at a little more that 2". Any suggestions on fix? Cut reweld an balance "machine shop" and what about u-joints
 
Depends on which yoke is on the 489. Worst case scenerio would be the offset U-joint for the 7260/7290 conversion!! Driveshaft will need to be shortened as mentioned above!! Geof
 
If you removed a 7 1/4 that was mated to a 904 from your car then your shaft will be to long.

There is some debate on how accurate this chart is so check it out for yourself.

This chart show a difference of 2.26" from 7 1/4 to 8 3/4-right? I am waiting for my 8 3/4 rear to be put together and will be doing this on my 65 Valiant. I plan to wait and actually measure the old drive shaft and mark it- I think there is a little variance on any swap. I'll let you guys know how it goes.
 
This chart show a difference of 2.26" from 7 1/4 to 8 3/4-right? I am waiting for my 8 3/4 rear to be put together and will be doing this on my 65 Valiant. I plan to wait and actually measure the old drive shaft and mark it- I think there is a little variance on any swap. I'll let you guys know how it goes.

Be sure and measure it correctly! I recommend calling the shop you plan to use and ask them HOW they want it measured so you are both on the same page when it comes to shortening it.

It should be measured with the full weight of the car on the suspension, not with the rear hanging.
 
When I first put the 360/8 3/4 in my 66 Dart,I used the driveshaft from a donor 73 Swinger 318/7 1/4 car.I swapped the u-joints to the 7260/7290 and bolted it in.Worked fine and ran 10,s with it after stroking the engine to a 410c.i.:D
 

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