The D inside the engine code stands for twin overhead camshaft (DOHC). That is attained by fitting an RB25DE or RB26DETT cylinder head and or turbo to a normal RB30E/T block. The RB25DET just isn't usually used. Equally Infiniti and Nissan have used the VH45DE engine. On the other hand, https://rb26enginesale61678.timeblog.net/64108092/the-greatest-guide-to-rb26-engine-sale