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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