Engine Swap -- Nissan 300ZX tt to a Honda Civic

Imposible !

Sorry but it's the real truth .

I've done motor swaps, and come up with crazy dream matches of engines to cars.  example - guy I know is buying a 225 hp japanese motor for his civic for $8500. For that much, I could build a small block chevy making more than twice the power and with low and midrange torque, and have money left over to fit it in the civic.  Back to the subject of the twin turbo nissan, it's theoretically possible, but it's infeasible if you're not willing to spend megabucks.  Two dreaming possibilities:

1. Put the motor in the civic using the existing drivetrain.  Honda transmissions, axles, and unibodies can reportedly handle much more torque than that engine makes.  However you would have to fabricate custom motor mounts, intake, exhaust and cooling system at the very least since the nissan motor wasn't designed for a transverse FWD application.  In addition, as far as I know Honda transmissions do not bolt directly up to Nissan engines, so you'd need to find a way around that.  This is all assuming you have the computer and wiring harness for the nissan motor.

2.  Swap an entire rear-wheel drive nissan powertrain into the civic.  This would involve suspension and body mods, and finding a transmission and rearend, but everything would probably work in the end.  This would probably be cheaper than option one (keep in mind, cheaper is relative, it would still probably cost at least $7000 when it's all done). 

So in the end, you'd spend far more than your civic is worth for either option, but you'd have a one of a kind vehicle

for you to put a 300zx in a civic, it is impossible, but if you have that much money you can thou.     it is better if you just go for a b20 vtec estimate at around 200 horse. then you build it and stuff. it will be around 2000 for the basic. or you want to go cheaper lsvtec turbocharge.  i don;t know why you want that much horse on a street car. just a plain b series engine will be good enough for street.