Extra usually a hybrid conversion with an RB30E block plus a twin cam RB25 head without having a turbo is usually used being a foundation for your RB30DE.The RB25DE cylinder head with the A31 Cefiro C33 Laurel or R32 Skyline (aka: Non VCT) may be used. The RB25DET (from your R33 Skyline or C34 Laurel or Stagea) head is usually used, having said tha