Technical Setting up a transverse rear spring suspension

Yes, it's a stock A spring.

 

Informative thread this one

 

you can see how i did an entire rear axle and transverse leaf spring swap in my 39 on page 17 of my build thread. it worked really well, and addresses the need to have the spring spread at the right width to load the shackles and set pinion angle on an open drive rear axle and not have the spring in a bind when you are done and at ride height.

Hot Rods - Bringing my 39 back to life | Page 17 | The H.A.M.B. (jalopyjournal.com)