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Author Topic:   Power valve vacuum
Dirt Full Roller

Total posts: 49
posted April 24, 2003 01:20 PM
Should be another easy question, last night I hooked a vacuum gauge to the intake manifold to read the vacuum so i could get the right power valve (2.5" under vacuum), the gauge read 12, when I revved it up it read 14 to 15.

Did I take the reading from the right place?
Or should of it been the carb vacuum port?

Or is the vacuum going to be lower when in gear (Muncie 3 speed), do I need to read it with transmission resistance?

Or did I do it right and need to install a power valve in the 10" range?

I want to start the year with the power valve and see how it works...

Dirt Freak

Total posts: 353
posted April 24, 2003 02:00 PM
If you are reading vacuum from an intake port or a full vacuum port on the carb then you have the correct source. If it was an automatic you would take the reading in gear but not with a manual.

Earl Parker II
Dirt Full Roller

Total posts: 39
posted April 25, 2003 09:16 PM
If your manifold vacuum is a fairly steady 12.0" then a 10.5" power valve should work fine. If you can't find one of those then an 8.5" will do.

Earl Parker II

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