The D in the engine code stands for twin overhead camshaft (DOHC). This is certainly accomplished by fitting an RB25DE or RB26DETT cylinder head and or turbo to a normal RB30E/T block. The RB25DET is not commonly used.The key thing to keep in mind to the RB25 sequence is going to be timely and good maintenance. As we’ll go into, the RB series all