Replacing 7.25 with 8.25

[6T6FISH]

I have a 66 Barracuda that I want to swap out the 7.25 with a 8.25 from a 76 Valiant. Can anyone tell me if it will bolt right up?

 

[Tooljunkie]

From my research it will fit. Driveshaft i cant answer, if diff is similar in housing size it may work. If u-joint is wrong, dont worry, there are conversion joints available.

 

[abodyjoe]

Yes it will bolt in. Driveshaft will have to be shortened if I remember correctly.

 

[brummett]

All A-body rears are the same width, so it'll fit. But it won't just bolt right up.

The shock mounting plates are different between 7 1/4 and 8 1/4 rears, so make sure to get those from the donor car. The snout on an 8 1/4 is longer, requiring a shorter driveshaft; a competent shop can shorten yours or make a new one. The 8 1/4 likely (certainly?) has axles with the 4 1/2 inch wheel lug pattern, while the wheels on your '66 are the 4 inch pattern. You'll need new wheels to mount on the rears, and unless you also change the front hubs (maybe by putting on disk brakes), you'd need to carry 2 spare tires.

 

[rich006]

The U bolts will be bigger too because the 8.25 axle housing is bigger.

 

[racerdan80]

8.25 has a 3" diameter axle housing so you'll need the right u-bolts and either slot the shock mounts or replace with new ones for the 8.25/8.75 axles

 

[Del]

Is the 7.25 a open or suregrip rearend