When installing aftermarket valve springs in a head assembly, the amount of load applied to each spring need to be adjusted until everything is in uniform specification. This is a standard procedure which all race engines go through in order to be able to raise the engine RPM without any glitches or hesitation. The standard method involved when putting together the valve assembly is to fully balance all the added components to tighter clearances than the manufacturer specifications. This method called gblueprintingh can be time consuming and a very costly service performed by an experienced engine builder. By utilizing the various thickness of the spring sheets to adjust to each and different spring rate load, the same objective can be satisfied with fraction of the cost. All of Tomei Poweredfs complete race engines are fitted and tuned with these valve spring sheets to ensure uniform specification for all areas that are necessary.