For starters the heads are a lot different. The intake ports are a lot larger ovals and the exhaust ports are circular instead of oval. Not sure about cams as I haven't measured them. The intake is completely different and so are the exhaust mani's. The turbo is actually of better design as well. The turbine blade is ceramic. The list goes on but this was over 10 years ago when I tried to install one in the 300 but the steering rack got in the way of the turbo but I always thought it could be dropped in a right hand side 300zx.