I have done several sets of eddys small and big block. What has worked every time on big block is adding a red or blue comp inner spring to the original spring with comp retainer #741-16 steel or 732-16 titanium. This is to get 340-350 at .600 lift and 150-160 seat pressure. The original springs are borderline to stiff for hyd cams and borderline to weak for solid cams. The original springs from edel. will work the way they are if not revving over 6000 rpm. If the edel. springs are new, the blue should work, if the edel. springs have a couple hundred runs on them try the red inner. red part#975-16, blue part#974-16. These are around $30 at summit. Steel retaners and locks will be around $80. tit. retainers will shock you at around $320 with locks.