Valve Spring Set Racing Dual (Set of 16) (1947-1979), T2 Bay (1968-1979), T2 Split Bus (1950-1967)A set of 16 heavy duty dual valve springs for use on high performance engines. These valve springs are designed for use in high performance engines that will be seeing increased revs over 6000rpm using a high performance camshaft. When running heavy duty valve springs uprated pushrods and rocker shafts must be used. Your cylinder heads will require machining around the valve guide boss when fitting these valve springs. These valve springs are suitable