the motor mounts are in a different location, and i will be offereing a kit for the FWD engines. the bellhousing position is the same. And it has been done before go on youtube and type in 240sx vq35de. You would use a 350z transmission and upper and lower oilpans.
YouTube - VQ35DE 350Z Motor HIGH COMPRESSION in 1989 240SX Coupe
that one is a Frankenstein vq using the maxima block
YouTube - vq35de 240sx twin turbo
that one is also a maxima block using stock ecus and dbw and is twin turbo
YouTube - 240Z w/ VQ Accel.
and this one is a VQ35DE revup installed into a 240Z using all the factory electronics from a 350z.