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Old 11-17-2011, 01:36 PM
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I hope your not running a distributor with no advance. If so your headed for a heart break. Right now you don`t have enough timing at idle and the butterflies are off the idle slots on the carb, if it idles at a 1000 RPM then shine a light in the carbs throat at idle and you`ll see fuel coming out of the boosters which means lack of enough base timing and idle set too high. This is why the idle and off idle doesn`t function correctly. Thumper cams are fad cams and they need alot of timing to run decent. You`ll need a adjustable vacuum advance. Set the base timing to 12 degrees before top dead center with vacuum advance disconnected and plugged. Reconnect it to a full time manifold vacuum source, one that pulls vacuum at idle. Recheck timing, it should be 18 to 24 degrees advanced, now lower the idle speed down to spec of around 700, use a vacuum gauge to set the idle mixture. Test drive, if ping is detected this is where the adjustable advance comes in. I figure you`ll need this with the small chamber 305 heads. Mechanical advance should be 36 degrees all the way in by 3000 RPM.
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