At 01:24 PM 3/21/99 -0500, CRAIG HALSTED wrote:
>I was looking through my U20 heads last week to pick a nice one out
>and came across one that had a couple modifications. behind the spark
>plug holes, where most have a built up ridge that makes a more
>distinct pocket around the valves, had been ground out and smoothed-
>would seem this might make for a more uniform flame front- is this
>what is referred to as "relieving" the head?
Usually "relieving" refers to opening up the combustion chamber around the
valves to reduce shrouding. It sounds like some racer was playing with the
combustion chamber shape.
>the water passages had
>been tapped and plugs threaded in. someone once told me this was an
>old racer's trick.
If you are talking about the water passaages into the intake manifold, yes.
It keeps the intake manifold cooler.
I have no idea what the deal is with the casting marks.
Gordon Glasgow
Renton, WA
http://www.gordon-glasgow.org
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