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Author Topic:   low vaccum
posted May 18, 2004 07:17 PM
i just got done building a 305 for stock class i put a small cam 440 lift flat top pistons ported and polished the heads the rest is basicly stock timming is 35 full advance at 3500 rpm im getting 16 to 17 inches of vaccum at 800 rpm i need 17.5 at 800 i was thinking maybe rings not seated yet
any ideas or comments apreciated thanks

posted May 19, 2004 06:30 PM
I was told you could run 1.6 rockers on the intake and run 1.5 rockers on the exhaust to gain vacuum. I havent tried it yet though.

Smith Racing Team

posted May 20, 2004 06:31 PM
If you have tried everything else, try using a set of variable duration lifters, like those offered by Rhodes. They are said to reduce the duration at low rpms, and restore it at higher speeds. Could work to increase your vaccuum.

posted May 20, 2004 07:20 PM
Have you tried adjusting the idle mixture on your carb. If not i woudl bet you could get to 17.5 by doing that.

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