The valvesprings are from Comp. With an outside diameter of 1.550 inches, Hafliger needed to open the spring pocket in the Edelbrock heads just slightly to make them fit. The installed height was 1.770 inches with 225 in-lb seat pressure. At 0.550 lift, the pressure jumps to 590 in-lb. Hafliger combined them with titanium Manley flat retainers and 10-degree locks.