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Power Valve

To: Tiger List <tigers@autox.team.net>
Subject: Power Valve
From: Bob Palmer <rpalmer@ames.ucsd.edu>
Date: Thu, 10 Aug 2000 08:19:49 -0700
Listers,

I have mentioned several times in the past that my engine runs best with 
way more spark advance than is normal. This, and other problems were all 
completely resolved when I replaced my old, faulty spark coil. I'm now 
running happily with 11 degrees initial and 36 degrees total spark advance. 
In trying to fix the symptoms, I made some changes to the carb, including 
changing the power valve. Now I want to adjust the carb optimally. I hooked 
up a vacuum gauge with a long tube so I could watch it while driving and 
determined that I probably wanted the power valve to kick in at around 10" 
of mercury. The 600 cfm, vacuum secondary Holley carb came originally with 
a 7.5 power valve and 64 jets. This was a bit lean for my motor, so I 
finally settled on 67 jets, but kept the 7.5 power valve. A few days ago I 
tried a different setup; I went to 63 jets and a 9.5 power valve. So far I 
like it a lot better than the previous setup. I may try a 8.5 power valve 
with the same jets and see if this still works as smoothly. I'm trying to 
improve gas mileage AND keep the motor responsive too. I realize the 
precise power valve and jets depends on the motor parameters, but what 
combination have any of you found that works well.

Bob


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