You could do the simple thing and call Jerry Cantrell at Schneider Cams. He can tell you in short order what spring is best and what are good alternatives. The number is (619) 297-0227 . I've been using Jerry's cams exclusively for over 40 years, in all types of engines (especially my favorite, flatheads) and never has he steered me wrong. Great guy and great product. And, NO I don't get any kick back. Just great performance!