CNC Mill Mark Removal in Intake Port

Dale Davies said

According to David Vizard, surface finish is not as important as the port shape and efficiency. You need to exercise caution on port volume as a larger volume creates a lazy port flow. Flow rate and the energy areof vital importance to cylinder filling.
Habit of a rough surface causes surface turbulence, which tends to toss fuel clinging to the surface back up into the air flow.

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That’s the problem with being a reader and not a doer.

Because port surface finish has an impact not only on power but on jet sizing as well.

If you can run 5 sizes smaller jet and make the same (or more) power the car will be quicker.

Darin Morgan already said you can’t make them too rough.

Larry Meaux says the same and he does the exhaust ports and chambers in a rough burr finish. Says he’s making more power the more he does it and the rougher he makes it.

Chad Spierer won’t do a manifold that isn’t burr finished. And some of his intake ports are burr finished.

Once again the claims made by DV and others because he’s not the only one saying it are found to be wanting.

If you don’t test you won’t know it.

Plus, I’ll say with pump gas or any alcohol based fuel today there is power in a burr finish.

You have to test it or you won’t know.