1NZ port & polish

[Moose]

OK, I can't read the Scion thread at work because it's blocked, so here's my experience with porting and polishing a head.

And Chino Charles, you are correct in that a P&P is, typically, one of the final steps, and is usually done to compliment your bolt-on power adders- but I'll help you out.

Standing alone, a P&P will gain very little- 15hp is realistic on our little engine- and that's with a very good, thorough job done on a flow bench including valve angles and fuel atomizing dimples.

Now, here is where it gets fun- adding very little to that, we can see much bigger gains- with just I/H/E, cams w/adjustable sprockets (springs and retainers, as well, by default), a fuel pump and injectors (a better fuel pump and AFR wouldn't hurt, either), and a piggyback. With these add-ons, and a dyno-tuner that knows what he is doing, you can make some really great horsepower and torque.

Cliffs?

You can P&P your heart out, but it all comes down to what else you have, and tuning, tuning, TUNING.