There is hardly a project out there as bitching as the motor swap. LS1 in a miata? Been there. SR20DET in a 240sx? Done that.
This particular Datsun 510 (old, small, lighter than whipped egg whites) has been outfitted with a 3 liter twin turbo VG30DETT from a later generation Z car. As one who as worked on a VG, I can testify that this thing is a pain in the ass (drop a tool? - forget it - it's gone) to wrench on when it's in a Z, much less something as diminutive as a cramped 510 engine bay. Holy power to weight ratio, Batman!