C-body center link has a larger pitman tapper hole. This kept from installing the more common parts on the bigger c-bodys.

Years a go I installed fast ratio power steering on my 70 dart.
This is what I did:
Got a C-body power steering box with the big 1.100 spline from the junk yard.
Had firm feel rebuild with the stage three kit.
Bought moog 67-69 Idler( K7014 ) and Pitman (1965 66 67 68 69 70~ K-7034 ~ K-7072) arms, and the bigger tire rod sleeves( ES2004S) and joints( inner ES355RL) (outer ES352R) .
Junkyard c-body center link.
I needed to modified:
The drivers side metal frame splash pan.
The idler to fit into the mount on the K frame.
Shorten the tire rod sleeves.
I have modified a B_body center link by opening up the pitman arm tapered hole. I guess the same could be done to an A-body.
Exhaust pipe needs to be moved back.
Pictures saved from other post.
This is a link I posted years ago on another mopar site.
https://www.forabodiesonly.com/mopar/threads/fast-ratio-steering-box.108037/

I like how the steering feels in my 70 dart. Like a modern car. No slop.
Planing on installing this set up in my 65 coronet, hopefully this summer.

Also have been collecting parts for manual fast ratio steering to be installed in my 66 valaint.