Valve Spring Set Triumph TR2, TR3, TR3B, TR4 to CT21470E that uses the large style valve springs. The Outer Diameter of the spring should be 1.400 Inches. These springs are a modern dual spring equivalent but use the same size valve cap. Don't skimp on your rebuild and take the chance of a broken valve spring that would ruin your engine rebuild. This kit is uprated and does not require the 3rd exhaust spring.