PAC Racing 1200 Series valve springs are great as replacement parts--or for pushing above and beyond the performance of OEM engines. Select them when you're upgrading camshafts or doing engine rebuilds. The 1200 Series use a premium alloy that outperforms automotive industry standards; and PAC Racing processes the alloy to aerospace shot-peening standards to achieve superior fatigue dependability. This ensures that the springs maintain the load needed to withstand rigors of both street and mild racing applications.