Originally Posted by MustangGT02
Just pick up heads for a great price and he told me they are ported and I know what that means but what does "valves have been undercut, they have had a 5 angle valve job, and have been milled 20 thousandths" mean?
Undercut valves are being referred to as the stems. Some use stock valves and some use undercut stems. You really need to have them flowed to know what you want and what application they are being used for. Since these are already in the head I'm assuming whoever did it flowed the head and they are better for many different reasons. So .020 has been removed from the stem of the valve where it tapers. Basically it's a narrower stem. 5 angle valve job would be referring to in most cases the valve and seat. The seat instead of being cut on one angle it is cut on 5 to improve flow characteristics. Hopefully that sums it up!
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