ok... i have a 92 nx2000, is it high or low port???

That would be a high-port:D

thanks bud!

What is a "high port" or a "low port" engine? Just different manufactures of the same engine?

the injectors are high in the head 91-93 then they switched to low port (the injector ports are lower in the head):D

The easiest way to describe it is by the Throttle body. On a high port the T/B is down low and on a low port it is up close to the hood.

The difference is where the intake ports are cast into the head. High-port head has the ports higher in the head for a straighter shot at the intake valves. In 1994, Nissan switched to low-port head design, with the ports cast lower in the head. I've never read why. It apparently didn't hurt power as low-ports respond the same as high-port heads to power mods. I presume this was an emissions and fuel economy measure. It's interesting to note that the '94 low-port made the same 140 HP and 132 ft/lb as a '91 high-port but with less pollution crap and milder cams.

High-port heads are characterized by the intake plenum lying low with the intake runners curling up with the injectors readily visible. Low-port heads have the intake plenum up high with the intake runners curling underneath.

I think I read somewhere that the lowport was for emissions purposes....maybe it runs cleaner.

It was primarily for emissions purposes. Even though the high-port head flows a little better, the runner length actually de-atomizes some of the fuel, causing emissions problems. The solution was to make a shorter runner (ie. low-port head). The result was a little more torque and midrange with about the same peak hp.