So........ What difference does it make???

Lift---before/after---difference
.100---58.5/67.2-----8.7
.200--123.6/146.4--22.8
.300--184.0/206.8--22.8
.400--235.6/246.8--11.2
.500--262.5/273.7--11.2
.550--273.0/275.6--2.6
.600--273.0/276.7--3.7
.650--268.1/277.5--9.4
.700--270.0/278.6--8.6

Keep in mind those gains are with a zero increase in runner volume or added cross section.

Another "nice" touch with the previous freshening was the way in which the valves were cleaned.
They were cleaned in what's known as a "tumbler", which is just what it sounds like.
Parts are put into the machines basket, which also has some sort of metal shot/media, and the basket rotates around and around, and the interaction of the media and parts removes the deposits from the parts.
The problem occurs when you put several valves in the basket at one time, and they bang and crash into each other, leaving little nicks and stress risers over the entire surface of the valve.

Tumblers are fine for cleaning certain things...... Valves aren't one of them IMO.