Is it worth changing 1970-72 spindles to 1973-74 spindles?

[Ornamental]

I'm going to upgrade my brakes, but before I pull the trigger I wonder if it's worth changing out the spindles from 1970-72 spec to 1973-74 spec at the same time to get the larger bearing?

[Mr Cuda]

I would say the primary reason to switch to 73 up is taller spindle height for better alignment specs when cornering,  and/or the ability to run 12" rotors.

[jt4406]

They also use larger inner wheel bearings.   jt

[larry4406]

How to distinguish 70-72 from 73-74 spindles?

[RUNCHARGER]

I always think that if the factory engineers thought an update was in order then it was a good idea for me too.

[dodj]

Yup...best time to do it.

[Bullitt-]

I don't know what you have now or what your plan is but it seems to me most of the aftermarket brake kits are made for the drum brake spindle or come with spindles...

[mtull]

I'm not sure this qualifies as "worth it" or if it's still relevant but nobody had new 11" rotors with the smaller 70~71 bearings during the COVID pandemic.  I haven't checked in a while so the issue may be OBE. The 11" rotors with the larger bearings were in very short supply but you could at least find them if I recall correctly.

[Ornamental]

I would say the primary reason to switch to 73 up is taller spindle height for better alignment specs when cornering,  and/or the ability to run 12" rotors.

Better alignment specs is a nice unexpected bonus.

I always think that if the factory engineers thought an update was in order then it was a good idea for me too.

It's a good rule of thumb, but one change may lead to unexpected consequences so I like to ask about these things.

I don't know what you have now or what your plan is but it seems to me most of the aftermarket brake kits are made for the drum brake spindle or come with spindles...

I have stock 1970 disc brakes.
The plan is Baer brakes.
They don't come with spindles, and they separate between 1970-72 OE disc spindles or drum spindles, and 1973-74 OE disc spindles for E-Bodies.

[Mr Cuda]

One important fact that I don't have the answer to is...., did the factory put 73 up b body spindles, which are the same as F,M,and J body, or use the A body 73-6 spindle on E bodies?
 All have the large inner bearing, and accept the same caliper brackets.  I suspect E body used the A spindle in those years.
 The 1973 B spindle shares the same part number through the car lineup till 1988.

[EV2RTSE]

How to distinguish 70-72 from 73-74 spindles?

One important fact that I don't have the answer to is...., did the factory put 73 up b body spindles, which are the same as F,M,and J body, or use the A body 73-6 spindle on E bodies?
 All have the large inner bearing, and accept the same caliper brackets.  I suspect E body used the A spindle in those years.
 The 1973 B spindle shares the same part number through the car lineup till 1988.

70-72 (B&E) on the right, 73-74E & 73-76A  on the left

https://www.forbbodiesonly.com/moparforum/threads/disc-brake-spindles-a-b-e-body-cars-1970-76.277668/

[Mr Cuda]

How to distinguish 70-72 from 73-74 spindles?

One important fact that I don't have the answer to is...., did the factory put 73 up b body spindles, which are the same as F,M,and J body, or use the A body 73-6 spindle on E bodies?
 All have the large inner bearing, and accept the same caliper brackets.  I suspect E body used the A spindle in those years.
 The 1973 B spindle shares the same part number through the car lineup till 1988.

70-72 (B&E) on the right, 73-74E & 73-76A  on the left

https://www.forbbodiesonly.com/moparforum/threads/disc-brake-spindles-a-b-e-body-cars-1970-76.277668/

Thanks EV2RTSE
As I suspected.
Maximum benefit is to use the F,M,J spindle which is taller and readily available.

[Brads70]

I went down this road a few years back. Depending on what your final "upgrade" looks like you may want to consider the 1973 C-Body spindle if you can find them as they are not plentiful and the C-Body crowd also looks for them to upgrade C-body's The problem with the E-Body suspension is horrible bump steer. One factor relating to the benefit of a taller  spindle is ideally the center of the upper ball joint should be slightly above the centerline of the upper control arms mounts in the frame rail. Problem is having it below ( as it is stock), is the camber arc goes out before it goes in during travel. This is horrible for handling in any car.
The 73 C body rotors are bigger and thicker and have the bigger bearings and cheap and plentiful. If you can find a donor car, grab everything, calipers, rotors. The spindles will require a trip to a machine shop to slightly slot the lower ball joint holes.
Read more in the link below if your interested...   
https://forum.e-bodies.org/wheels-tires-brakes-suspension-and-steering/12/-using-c-body-spindles-on-an-e-body-and-a-body-lcas-and-viper-calipers/58/

[mtull]

This is horrible for handling in any car

@Brads70
Since you have experience driving a non factory setup, would you please elaborate?  Would you consider stock setup to be horrible handling for everyday cruising or in specific situations?  Everyday cruising would also include emergency stops and avoidance as well.  If you think my questions will take this thread too far off the course please ignore.

[Brads70]

This is horrible for handling in any car

@Brads70
Since you have experience driving a non factory setup, would you please elaborate?  Would you consider stock setup to be horrible handling for everyday cruising or in specific situations?  Everyday cruising would also include emergency stops and avoidance as well.  If you think my questions will take this thread too far off the course please ignore.

S

This is horrible for handling in any car

@Brads70
Since you have experience driving a non factory setup, would you please elaborate?  Would you consider stock setup to be horrible handling for everyday cruising or in specific situations?  Everyday cruising would also include emergency stops and avoidance as well.  If you think my questions will take this thread too far off the course please ignore.

Sure, might be best to read my linked post though as to not derail the original post. The other spindles are much easier to find and are a simple bolt on.
My issue was as much as I loved my 70 Challenger it was the worst handling car I ever owned. The last straw if you will was when the wife's 6000LB suburban out handled and braked my Challenger.
Depends what your happy with? Most people accept its a 50 year old car and their shortcomings, and really only drive to the occasional show or take the grandkids out for ice cream. Stock stuff is fine for that. Or if your car is a rare 100 point show car then I would leave it stock. Mine is just a /6 car originally so I won't be hurting the value. I drive mine everywhere and as much as possible and was tired of having to brake at every corner and slowing up traffic behind me.

For the OP, if you already have rotors etc... I would use what you have till they wear out then think about replacements. In the mean time might be a good idea to gather the required parts that will be harder to get as time goes on. Spindles , caliper adapters...