Dave
I can think of 3 or 4 cases of people wanting to drop a VH/VK v8 in a GTR, one mob even started doing it.
None were ever finished, even with a huge budget.
the VH/VK V8s are a very big engine for only 4L, so much so that they would be heavier than a RB.
If you want to be Different than look at getting a rebuilt FR9 or R5P7 Nascar V8, 850+hp on E85, and will last until the end of time in a hot lap car.
Also they are going to Fuel Injection next year, so the likes of Roush/Yates will be doing all the R&D For you