Mine has only had springs in the last 300 passes. Comp RX 1718 int lobe, XCX 1862 exh lobe. 2.25" Ferra 6190VB int, 6188 exh, Pac 404 retainer. The Pac 1224 springs I took off (200 passes) tested with-in 2% of the new springs. The old springs actually had the higher pressure. Lash seldom changes more than .001"-.002" on lash checks. Usually 4 valves or less need adjustment. Very bracket friendly. Normal RPM limit 7200.
Doug