Much more usually a hybrid conversion using an RB30E block and also a twin cam RB25 head with no turbo is usually used being a basis with the RB30DE.The RB25DE cylinder head with the A31 Cefiro C33 Laurel or R32 Skyline (aka: Non VCT) can be used. The RB25DET (from your R33 Skyline or C34 Laurel or Stagea) head is also used, having said that an ext