Bob:
Porting the head will help at ANY level of tune. You get more
when the engine
is in a higher state of tune, but it will help even stock. Think 10%
gain. Probably
the second best bang for your buck on any motor. Exhaust system
(muffler, pipes)
is probably the best deal going.
I am of the mindset that a 3-angle valve job and back cutting
the intake
valves are part of a good port job. Forget gasket matching or polishing.
They
are a waste of time. Wear a face mask, or you will be tasting iron for a
week
(ask how I know).
Polishing the valves and necked stems are also helpful, but are
starting to get
into diminishing returns. You can machine your existing valves, or
purchase custom
valves. Depends how much you want to spend.
The later head needs less porting that the earlier head, as the
port design is
superior on the later head. Course the PI motor had the better ports all
along,
which is partly why the PI motor made more power.
Get one of Vizard's books to see the shape you are aiming
for....
Cheers,
Vance
-----Original Message-----
From: owner-6pack@autox.team.net [mailto:owner-6pack@autox.team.net] On
Behalf Of RazorBobSr@aol.com
Sent: Tuesday, August 17, 2004 5:52 PM
To: 6pack@autox.team.net
Subject: Hello Gents
At what stage or level of an eng build would porting a head start to
help the
eng HP???? I have a 6 pot,9.5,twin 1 3/4 SUs,mild cam,header,and now
starting
to think of winter projects
Check out the new British Cars Forum:
http://www.team.net/the-local/tiki-view_forum.php?forumId=8
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