theres 2 ways you can do it
one involved custom crossmembers, tailshaft, diffs, manual conversion, suspension, wider wheels, fuel system, manual pedalbox, customer hydro clutch setup, intercooler piping, dump pipe and exhaust, mounts, pluss everything to make it emissions legal.
or for the much easier, and likely cheaper way its a nice and simple 3 step process
1. jack up the ke70's radiator cap
2. slide ca18det powered 180sx/silvia under radiator cap, lower radiator cap to its orginal height
3. replace the radiator cap.