will a project mu BBK that was for a 350Z fit a 370Z?

OptionZero

Mounting points are different

HOWEVER, my understanding is the project MU has a few standard caliper sizes and then just makes an application specific bracket

I would contact Priject Mo’s North American distributor and see if they can just give you the right bracket:

Project Mu Co., Ltd. - DISTRIBUTOR

It’s Mackin Industries, who brings over Project kics, rays, Advan, etc

I also DM’d my jdm parts guy to see if he knows. Stand by


UPDATE:
Yeah, sounds like you can swap the adapter
But you may want to also upgrade rotor size

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