It is the valve seat that they are refereing to. The seat of the valve is the part of the valve/head that touch one another when the valve is closed.
Typically there are three angles on a valve.
Sometimes you can get five angles.
The "best" is a fully radiused seat.
The reason for multiple angles is because it improves airflow from the valve at partial lift.
Yes, valve jobs in general are expensive. Especially when doing it for performance.
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BRacing
"Going faster since 1994"
"Drag racing is for those that can't steer"
Typically there are three angles on a valve.
Sometimes you can get five angles.
The "best" is a fully radiused seat.
The reason for multiple angles is because it improves airflow from the valve at partial lift.
Yes, valve jobs in general are expensive. Especially when doing it for performance.
------------------
BRacing
"Going faster since 1994"
"Drag racing is for those that can't steer"