hello I’m currently working on the same , 2007 G35s car putting a 2011 g37 engine in it. Wondering what engine harness to use ? The g35 or g37 or will i need something else ?

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Since you're swapping engines from a VQ35HR to the completely different VQ37VHR you're going to need everything from the VHR platform, engine, transmission, wiring harness, ECM, everything. Expect to modify things like power steering pump lines, etc. They make some CANBUS converters so you can get most of the dash instrumentation working but there are still things that won't function.

Just google search "vq37vhr swap 350z g35" and you should find a few links to things like the converters and such.