What are the differences in the A and B body Idler and Pitman arms?

[Kern Dog]

I'm gathering parts in anticipation for a swap from the Firm Feel Stage 3 steering box with Fast Ratio arms to a Borgeson unit with stock arms. This is in regards to my '70 Charger.

I have collected parts for years and most of it is UNmarked. In many cases, parts will physically interchange between A, B and E body cars.
I am rifling through my steering parts and have found several idler and Pitman arms that are in good condition. Their appearance varies but that could be due to some being originals, others being aftermarket stuff.
I checked Firm Feel and Rock Auto and they do show different part numbers for A VS B models.

These are all the same sector size. Notice the differences:

They all appear to be the same length.

The two on the right have that banana curve but the 4 index marks are the same.
Could all four of these be for B body cars? If so, that is odd since I have parted out a LOT of A bodies and only one B body.

Check out the Idler arms....

If these are for an A body, It would be the 73-76 models since the early A has the stud pointing UP.
The two on the right are quite robust. ALL also appear to be the same length.
This picture below is with the Fast Ratio arms. Note the banana curve in the Pitman arm.

That at least leads me to believe that the two curved Pitman arms are likely to be correct.
That leaves the Idler. Both my red car (Ginger) and Jigsaw have Fast Ratio arms so I don't have anything to compare to properly identify the Idler.
If the A and B are the same length, mount the same and have the same "drop" as well as the taper in the mounting stud, I don't see the difference. Do you?

 

[DeltaV]

Check the lug thickness (splined end) of the pitman arm too.

Around 2001 NAPA sold me an aftermarket (Moog) pitman arm for my '79 300. The lug was too thin and the nut bottomed out on the shaft instead of clamping up on the lug. Took it back for a refund. Got lucky and found the right one sitting on a Chrysler dealership shelf in New Jersey.

 

[Kern Dog]

I suspect that I had my factory Pitman in the stash......

I forgot how much longer those Fast Ratio arms are. Besides the 12 lb weight loss with the Borgeson box, the shorter Idler and Pitman may result in another 1/2 lb loss!

 

[steve340]

It makes it a bit harder as nothing is marked.
So long as everything ends up the same place you would be OK. A flat table, some shim blocks, square and a marker pen will sort of tell you.
I know the pitman arm and idler arm are the same so they swing through the same arc.
Also when mounted the centre link should be parallel to the ground and lined up straight across the car when you look side to side.

 

[Kern Dog]

From what I have gathered, the 1972 model A body was the last with the small shaft/spline size for the Pitman and for the Pitman stud pointing UP.
In 1973, the A body steering linkage changed a bit.
The Pitman and Idler studs pointed down and the Pitman shaft went from 1 1/8" to 1 1/4".
With that info in mind, the Pitman arms that I have are all small spline so that must mean that they are 1972 and earlier.
The 2 that I posted with the banana curve look like the Fast Ratio Pitman that I have.