Hey guys, just though I would chime in with a machinists point of view. Building 225-250 is not a problem with that engine. Building it to be streetable and pass CA emissions is another story entirely. Is this your daily driver? Do you know how much clutch pedal you will need to contain 225 HP and how tired your left leg will become when cruising around? Do you have plans for a computer and fuel system to handle it?

I can tell you that I did some mild port work, a good valve job, bumped the compression to 11:1 and the mildest cam above stock that Crower makes with new stock valvesprings on a customers D16Y8 picked him up over a half second in the 1/8 mile while frying his "high performance" clutch and getting no traction with the tires. I doubt the engine makes 155rwhp and he is just behind his buddies 4.6 mustang at the drags. This is a totally streetable combination using the stock computer and fuel system and was relatively low budget. A fully ported head (correctly done, not hogged out), a good cam and valve springs, and a really well done computer (Mugen) could easily bring the combo to 170-180+hp and still be plenty streetable. In my opinion, unless you add some kind of power booster, that is going to be about all you are going to reasonably get and still be good for a daily driver and might be able to pass smog tests.