Does anyone know how much of a power gain a mild to aggressive street port gives on a n/a car with mods.

 

Well, you do lose some low end torque, but it isn't really noticeable at all. (I was told you would only notice it on a dyno, and I beleive it) On a six port engine, you will gain a good chunk of high end, much better than stock. Don't expect instant turbo power though. It might give 20 or so extra HP, all at top end. It does make any intake and exhaust mods work better though, increasing everything. It opens things up for crazy flow- so I would only recomend it for a whole bunch of mods. It will also in increase your redline by about 500 rpms before power starts to fall off.