How Do You Increase the Spring Travel?
The valve spring must have sufficient travel (plus .060" safety margin) to accommodate the amount of valve lift created by the camshaft and/or an increase in rocker arm ratio. To increase spring travel you can either raise the installed height (but this will lessen the spring tension), or change to a spring with additional travel. If there is not a standard diameter spring available with enough travel, then the cylinder heads will have to be machined and a larger spring installed.
Crane Cams offers some special valve springs in standard diameters which saves you from having to machine the cylinder heads. For example, a small block Chevrolet engine can use spring kit part no. 11309-1 to handle .550" to .600" valve lift. The 85-95 302 Ford hydraulic roller engines can use spring kit part no. 44308-1 to handle .550" lift.
Crane Cams offers some special valve springs in standard diameters which saves you from having to machine the cylinder heads. For example, a small block Chevrolet engine can use spring kit part no. 11309-1 to handle .550" to .600" valve lift. The 85-95 302 Ford hydraulic roller engines can use spring kit part no. 44308-1 to handle .550" lift.