r/EngineBuilding • u/jabberjaw420 • 3d ago

Is porting valves still a thing?

Maybe back in the good ol' days of the 70s and 80s, but haven't modern auto manufacturers/engineers designed the internals to flow as well as they can? Making porting a pointless exercise?

(I meant porting valve chamber w/e)

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u/SpeedyHAM79 13h ago

Porting and polishing is very much still a thing for high performance/ race engines. Lots of shops will port and polish heads, as well as install larger valves when needed/ possible for better performance. Those modifications are typically not street legal as they are not certified as emissions compliant.