The D during the engine code stands for twin overhead camshaft (DOHC). That is accomplished by fitting an RB25DE or RB26DETT cylinder head and or turbo to a regular RB30E/T block. The RB25DET just isn't commonly used.While this isn’t a lot of an engine flaw as much as it is a structure flaw, it does have an impact on the RB30ET inside the Holden … Read More