It will seal better! Think of it like a lip that produces greater sealing clamping forces. For those of you who don't know, take a look at this:
Here is some information on what o-ringing your block is. This short excerpt is taken from
Wayne Chin's Subaru Page.
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<TD>[font=Trebuchet MS, Arial, Helvetica]Here
is a quick diagram of what o-ringing is all
about. The idea is mainly to provide a much
higher clamping force on the head gaskets using a
small metal ring.[/font]
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[/font]
</TD>
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<TD>
[font=Trebuchet MS, Arial, Helvetica]
[/font]
[font=Trebuchet MS, Arial, Helvetica]
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<TD>[font=Trebuchet MS, Arial, Helvetica]This
is what an o-ringed head looks like.[/font] [font=Trebuchet MS, Arial, Helvetica]Not much
here, except for the two thin rings added to the
head surface. This excellent example of
craftsmanship was performed by Charlie North of
Function First Motorsports in East Wallingford,
VT. You should be able to find a highly skilled
machinist to do a similar job.[/font]
</TD>
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