I was reading an ebay post about some heads. They are 351 Cleveland 4V heads. In the discription, it says they have had a 3 angle valve job? What does this mean? Pardon my ignorance.

 

i doodled on this pic so you can see the 3 angles cut into the seats. it basically smooths flow from the port into the chamber - honestly, heads pretty much come with 3 angle valve jobs from the factory.

(small block chevy head shown)

 

Thx...that makes sense.