I have read that 41 Fords are a bit different than others re: springs regarding angle of shackles. Read this:
https://www.independent.org/store/book.asp?id=90
Considering the amount of work it takes to install a spring I would go with a correct new spring. Call Eaton and get first hand, accurate info.
https://www.eatondetroitspring.com/a...-super-deluxe/
Also, call Posies. Posies and compare their info. with Eaton.
https://www.posiesrodsandcustoms.com...35_48_springs/
First, look for a NOS Ford made spring for your car.
Also, buy new shackles.
https://www.jalopyjournal.com/forum/...e-set.1044554/