Which 8.25 do I have?

[Mr. PNW]

We are swapping out the front drum brakes and rear end on our 68 slant six cuda with the 4" bolt pattern for disc brakes out of a 73 Dart with the 4.5" pattern.
We swapped the front brake parts today and it is back on some 15" stock Coronet wheels.

Our next step is to swap in a 8.25 rear end I picked up a number of years ago that also has the 4.5" bolt pattern. I know I will need a set of shock plates and 3" u-bolts. We are going to drop in some new Mopar XHD springs.

Is there a way of knowing for sure which model of vehicle this rear end came out of?
I measured between the spring perches and it looks to be about 43" center hole to hole. The measurement between the backing plate at the outer lip is about 48".

 

[Inertia]

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There is an incorrect 8 3/4 axle length,, but the 8 1/4 measurements are correct, to the best of my knowledge..

hope it helps

 

[Mr. PNW]

Found this;
It looks to be a 69-70 B-body from this info but the lengths don't seem right. Could the pumpkin have been swapped?

http://www.drivinithome.com/rear-axle-identification/

 

[dodgedartgt]

Not with it having 43" spring pad center to center. That is definitely A-bdy measurement.
I would expect that center section casting number was assembled into any of the different housing lengths, not JUST 69-70 B-bdys.

Mike in FL

 

[Ben Drinkin]

So if i swap an 8.25 from a 73 dart to replace the 7.25 in a 69 barracuda (assuming all original stuff), It will be almost an inch shorter per side? Does this create any tire fitment problems?

 

[RedFish]

So if i swap an 8.25 from a 73 dart to replace the 7.25 in a 69 barracuda (assuming all original stuff), It will be almost an inch shorter per side? Does this create any tire fitment problems?

I cant see where you got a inch shorter per side from the chart above. I see about 3/4 difference overall which would be 3/8 per side to the back of the backing plates but then how far the axle flange stands out could throw it either direction yet again.

 

[RedFish]

OOPs my bad the chart does show 53.2 versus 51.4 What's that about 7/8 per side ?
Still axle length is a factor. The 8.25 surely has wider brakes that the 7.25

 

[1970Duster]

Remember the 8.25 can easily be upgraded to rear disc brakes a from a jeep grand Cherokee.

 

[dartnabout]

This is cool information.

 

[crackedback]

Unfortunately that chart is a POS.

43" perches says A body or an A100. If the axle flange length, where wheels bolt on, is about 57.25", it's an A body rear.

If the rear is total in the 60" range it's a B body or something else.

 

[RedFish]

Remember the 8.25 can easily be upgraded to rear disc brakes a from a jeep grand Cherokee.

Some have discovered they need different wheels after the rear disc install.