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Crate motor fully blueprinted, new carb Holley 600 cfm. The engine knocks under acceleration. Sounds like a diesel motor. Timing is all correct. We've tried taking some timing out and putting extra timing in and the motor still knocks. Does anyone have an idea of what the issue could be?! I know this is a general question and I don't have much info on it. I am posting this for my father who does not visit sites like this. Thanks in advance for any replies!!
 

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Crate motor fully blueprinted, new carb Holley 600 cfm. The engine knocks under acceleration. Sounds like a diesel motor. Timing is all correct. We've tried taking some timing out and putting extra timing in and the motor still knocks. Does anyone have an idea of what the issue could be?! I know this is a general question and I don't have much info on it. I am posting this for my father who does not visit sites like this. Thanks in advance for any replies!!
Detonation is related to either timing or compression/octane issues. I would double check the timing. Did you degree the camshaft? I think some cam gears are designed to allow some retard or advance at installation. If the compression is too high, and your using low octane fuel, detonation (knocking) will occur as well. 18436572, Good luck. A call into the builder would be my next step.
 

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If you have vacuum advance on the distributor hook it up to manifold vacuum below the butterflys on the carb. You can hook it straight to the intake manifold just dont hook it to port vacuum above the butterflies. You want it to retard the timing when you accelerate not advance it. Actually it doesn't retard it but it just takes the vacuum advance out of the equation when accelerating.
Also use the highest octane grade you can find.
 
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