The D from the engine code stands for twin overhead camshaft (DOHC). This is certainly completed by fitting an RB25DE or RB26DETT cylinder head and or turbo to a typical RB30E/T block. The RB25DET is just not generally used. Nevertheless it’s not as talked about as many of its cousins, https://hectoruxvrs.blogozz.com/27860060/not-known-details-about-rb26-engine-sale