Port and polish

[niky]

A port and polish is basically that, the intake and exhaust ports in the cylinder head are enlarged and smoothened, and the air passageways are straightened and evened out. This minimizes turbulence in the air going in and out of the combustion chamber. The "polish" basically smooths the finish to eliminate turbulence caused by the rough surface finish of those ports... although a good PnP will leave a bit of roughness near the intake valves, as some turbulence near this area helps "swirl" the air-fuel mixture, allowing it to "mix" better for a more even burn.

PnP is an art and a science. Do it wrong and the cylinder head is ruined. Do it right and you can unlock a whole lot of potential.

Blueprinting can be done alongside PnP, but it's completely different. In blueprinting, the engine is balanced and rebuilt to a very exacting specification... valve clearances fixed. All piston and rod weights made identical (or close as possible), the crankshaft balanced properly, the piston-cylinder wall clearances and piston-ring gaps fine-tuned, etcetera... all of this allows the engine to rev higher and with less stress, and to either make more power or last longer... or both.

Now... blueprinting IS an overhaul. But like PnP, it's not really needed for a street engine... depending on how old the engine is or what its condition is.

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Both popular in the old days. Nowadays, engines are better built, and any gains from doing this are more marginal. Hell... some engines, you have to shed blood, sweat and tears to see even the tiniest gains from stuff like intakes and exhausts, where in the old days, even the cruddiest exhaust work would gain you a whole lot of horsepower.

Nowadays, electronic engine tuning, either via a standalone ECU or a piggyback controller, is the big ticket item. And unlike a PnP or blueprint, you can uninstall a piggyback when you're sick of it.