Holley PN 20-13 you'll need to order 2 kits, total approx $30 use genuine Holley parts, you don't need any further issues

Generally I start with the white springs, and move up the spring range to tailor the opening rate/rpm of the secondaries, rather than working downward from Brown or Black springs...I prefer the secondaries coming in as earliest as possible, and basically as demanded by my right foot, rather than "waiting" for the system to overcome high spring tension in the secondaries

Mike