Which Valve Springs with Purple Shaft P4102661?

Good morning all,
I cant seem to find the information on spring rates anywhere for this cam. Its the older Mopar Purple Shaft grind. Working with a head manufacturer and exploring some options, but neither they nor I can seem to find the required spring information. I've checked Summit, Jegs and Mancini.

Anyone running this cam, and what springs are you using?
Thank you.