Turning to Tom Walkinshaw Racing (TWR), Nismo began developing a prototype of the R390 GT1, named to follow in the tradition started in the 1960s with Nissan's R380. The first decision for Nismo and TWR was the choice of engine. The previous Skyline GT-R LM had used the trusted RB26DETT Inline-six engine, but the design was old for a racing car, employing an iron block which added weight and had a high center of gravity. Nismo instead chose to resurrect an engine from the Nissan R89C, a racing car from the Group C era. Its powerplant, the VRH35Z, was a V8 engine which used an aluminium block, as well as having a lower center of gravity and a better ability to be used as a stressed member over the RB26. Thus the engine was modified and designated VRH35L and would produce approximately at 6,800 rpm. For the road going version, the engine was detuned to .