300 I6 Low end Knock

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Sep 7, 2009 | 04:00 PM

8525ford

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300 I6 Low end Knock

recently swapped out the eec iv igniton for the duraspark 2. Swapped out the manifolds for a clifford performance, and hooker long tubes, and have a holley 4 barrel to top it off. The truck starts and runs ok. The timing is about 10 degrees advanced. Problem is when i just crack open the throttle i get a loud knocking noise, and then as i rev it up it fades out. Could the carb be in need of adj. timing to advanced?? i put 93 octane in it and it didnt go away. need some things to try.

also when i take it out and drive it, if i really stomp on it
the truck falls flat on its face and bogs down bad?? thanks

Sep 7, 2009 | 04:45 PM

81-F-150-Explorer

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Joined: Jul 2004

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From: Northern California

Some 300's were timed at 6 degrees depending on calibration.

Try adjusting the timing.

Also your timing curve on the vacuum advance could be way off.