[TWX]

There were 8¾ differentials in A-bodies. One of those axles '67+ should bolt right in. The A-body is also a popular drag car, and I would expect that there are aftermarket or Mopar-Performance-aftermarket 8¾ axle housings or complete axle assemblies available, though probably fairly pricey.

Just to confirm, you do know, for certain, what your wheel bolt pattern is, right? There were two patterns common on the A-body, the 5 on 4.5", and the 5 on 4". The smaller was just about ubiquitous early on, and the larger was common later.

 

[TWX]

In my understanding, the 1975 Valiant has the 5x4.5" bolt pattern if it has front drum brakes. It has 5x4" bolt pattern if it has front drum brakes.
All A body 8.75" axles were from earlier years when all A bodies had 5x4" wheels.

You meant 5 on 4.5 if disc, right?

 

[TWX]

Honestly, the axle tubes/housing part and the axles shafts are probably the harder part for an A-body to find than the removable center section differential, which will be common with all of the same generation of the differential.

I would think that you would do well to buy this one, identify which generation of 8¾ the axle and differential is, and to use it as-is until it fails, then deal with a new center section or new parts for a more thorough replacement of the limited slip or locker in that center section after such a failure, or maybe if you proactively feel like changing it. The axle housing itself, and the axle shafts should be the same.

 

[TWX]

It *appears* from what I've cursorially read that the axle housing with your 741 center section will accommodate 489 or a 742 center sections as a replacements, and that the limited slip module is the same in all three. The difference between the three is in the pinion gear and ring gear and how the pinion slots into the casing.

 

[TWX]

I would get some disc brakes for the front, with the 5 on 4.5" pattern, and get wheels for 5 on 4.5" as well, which are REALLY common since Ford and AMC also used 5 on 4.5 in addition to virtually all Mopars...

 

[TWX]

The first generation Dakota also had a 9¼ in some years, but I'm not 100% sure which years. The trouble with the Dakota as a source is that they switched from the five lug 5 on 4.5" hubs to a six lug pattern when they went to the rounded front snout and available V8 engines, so it's possible that they never used the 9¼ in the Dakota until the six lug pattern became standard. Since a lot of engineering in the Dakota was borrowed from the F/J/M body (Aspen, Volaré, and the like) it's likely that a Dakota rear end could be adapted to the power required, and with modern improvements in brakes, might have better factory brakes than anything factory from the earlier years.