7 1/4 to 8 3/4 in ‘67 Dart

[VintageRacer67]

Hey FABO. So I pulled my old rear end out and am getting ready for a swap, 7 1/4 open to a 8 3/4 suregrip (3.73) in my 1967 Dart (318/904). After some FABO research, I wanted to clarify a few things that I’ve read on other posts.

I know I need new shock plates and u-bolts. Is it correct I also have to shorten the drive shaft and replace the U joint? Anything else I’m missing? This is my first rear end swap so any advice or pointers would be great.
Thanks!

 

[tonysrt]

The axles can be big bolt, 41/2" or small bolt pattern 4". Just something to think about, older cars have small bolt pattern up to 73.

 

[318willrun]

Hey FABO. So I pulled my old rear end out and am getting ready for a swap, 7 1/4 open to a 8 3/4 suregrip (3.73) in my 1967 Dart (318/904). After some FABO research, I wanted to clarify a few things that I’ve read on other posts.

I know I need new shock plates and u-bolts. Is it correct I also have to shorten the drive shaft and replace the U joint? Anything else I’m missing? This is my first rear end swap so any advice or pointers would be great.
Thanks!

• shock plates - you can drill your 7.25 plates or get 8.25/8.75 plates
• u-bolts - yep, buy new
• drive shaft - yep, needs to be shorter
• u joints - they make adapting u joints to go from wide to narrow if you end up with that scenario
• Not sure if your 8.75 rear end came with backing plates/drums, but you'll want to check that out
• brake lines are pretty straight forward, but the vent tube may be in a different location so sometimes a longer brake line is needed
• as mentioned above, check the bolt pattern

 

[VintageRacer67]

• shock plates - you can drill your 7.25 plates or get 8.25/8.75 plates
• u-bolts - yep, buy new
• drive shaft - yep, needs to be shorter
• u joints - they make adapting u joints to go from wide to narrow if you end up with that scenario
• Not sure if your 8.75 rear end came with backing plates/drums, but you'll want to check that out
• brake lines are pretty straight forward, but the vent tube may be in a different location so sometimes a longer brake line is needed
• as mentioned above, check the bolt pattern

Thanks 318, I appreciate the comprehensive list. Shock plates and U bolts I’ve purchased. I’ll get a new rear brake line for a 8 3/4 rear. Now for the drive shaft… any idea how much it needs to be shortened by?

 

[VintageRacer67]

The axles can be big bolt, 41/2" or small bolt pattern 4". Just something to think about, older cars have small bolt pattern up to 73.

Thanks Tony. It’s a large bolt pattern, to match my large bolt pattern disc swapped front.

 

[318willrun]

Thanks 318, I appreciate the comprehensive list. Shock plates and U bolts I’ve purchased. I’ll get a new rear brake line for a 8 3/4 rear. Now for the drive shaft… any idea how much it needs to be shortened by?

measure it. Slide the yoke all the way into the tranny, then measure the center to center of the u-joints, then subtract 3/4" to 1" from your measurement so the slip joint can do it's job.

 

[Dana67Dart]

measure it. Slide the yoke all the way into the tranny, then measure the center to center of the u-joints, then subtract 3/4" to 1" from your measurement so the slip joint can do it's job

With the car sitting on all 4 wheels with normal weight

 

[318willrun]

With the car sitting on all 4 wheels with normal weight

yes, if your skinny or working on a truck. For a A-body, rear axle on jack stands will give the same results and allow most of us to get underneath lol .

 

[Topless69]

If you haven’t already you may want to replace your springs, and check the bushings in the shackles

 

[RustyRatRod]

Small bolt pattern was to 72. Also, I believe the drive shaft difference is 1.5" if I remember right. But measure first.

 

[VintageRacer67]

If you haven’t already you may want to replace your springs, and check the bushings in the shackles

Thanks for the recommendation. I already have new Espo springs and shackles sitting here ready to go in.