Help with an 8 3/4 swap

[Kevo]

I just replaced the 7 1/4 rear end in my 68 dart with a 8 3/4 from a 65 coronet. It has already been shortened to size, but im not sure if the drive shaft will need to be shortened. I have the rear end in, but not bolted down, and it seems like the drive shaft is only off by about 1/4 in, i figured if i tightened it down it would fit, but after some research it doesnt seem like it will.
Does anyone know for sure? if so, how much would i need to cut off?

All help is appreciated!

 

[fishy68]

From everything I've read you would need to shorten it 2-1/4" because that's how much more the 8-3/4 pinion yoke sticks out, but not all information on the net is accurate so you should measure. You do that by having the car setting on all 4 wheels and slide the slip yoke into the trans. and pull it back out 3/4"~1" and measure from the center of the U-joint cap on the slip yoke to the center of the u-joint cap on the rear end yoke. That's how long the driveshaft needs to be center to center.

 

[d5667]

That is correct.When you frankenstein these cars all the chart numbers are no good.Bolt the rear down before you measure,don't leave anything to chance

 

[67Dart273]

You have to have the car sitting "normal" with weight on the wheels. I don't know how else you would do it except "bolt it in" But before you do something that expensive, I'd make sure your rear springs are "what you want." I did a real low budget backyard deal with mine---I junked out (actually a couple) of Duster/ Demon cars, and tore apart one set of springs off one car. Took those leafs and my originals, and "double stacked" all the longest leafs from both sets. I believe I have one more leaf than stock, but the bottom leaf is longer than original. It raised the car a little but really stiffened it up nice.

I don't know how big your area is, but even here you can buy center bolts and spring clips.

 

[Bill Dedman]

You should measure. You do that by having the car setting on all 4 wheels and slide the slip yoke into the trans. and pull it back out 3/4"~1" and measure from the center of the U-joint cap on the slip yoke to the center of the u-joint cap on the rear end yoke. That's how long the driveshaft needs to be center to center.

What he said. If the weight is on the 4 wheels, this is fool-proof and easy.

 

[Kevo]

Awesome, thanks guys!