What a three-angle Valve Job IS

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Hot 6t Falcon

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A common question is what is a three-angle valve job. In an attempt to explain, I'm including some sketches out of our Performance Handbook. A picture is always worth a 1000 words.

First a sketch of a "stock" rebuild so you can see what Ford intended.

Stock.rebuild.drawing.jpg


Now a sketch of the three-angle cut. Some people make a four angle cut by adding a 60 degree cut down into the port bowl.

3-angle-drawing.jpg



The cuts are not made to the valve, but rather to the valve seat.

A "backcut" can be made to the valve that will trick the engine into thinking that it has a higher lift camshaft. On a stock valve there is a pronounced lip where the second cut is made on this modified valve.

back-cut-valve.jpg


We don't recommend doing a backcut to an exhaust valve except on a "race-only" engine. The exhaust valve absorbs a lot of heat and needs its mass on a street engine.

Please start a new topic to ask questions.

Good Luck
 
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