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Discussion Starter · #1 ·
So I just got my '72 on the road for the first time in awhile. There is a knock under my hood of my 454 and I am not sure of the difference between knocks from piston slap, detonation etc. It only occurs every 5-8 seconds and sometimes not for 10 but not really at a consistent interval. It increases in both frequency and volume under load, and I can feel it in the gas pedal. It is not so much as a click more of a thud. My guess is detonation, but I don't know squat about engine noises and I will not be able to adjust the timing on it until later this week and I'd love some piece of mind while i wait. I assume that if it was from an engine component hitting another engine component it would be at a more rapid and regular interval, right? Thanks for any advice you can give me.
 

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could it be a broken motor mount. Open the hood and start the car, put it n gear with foot on brake in forward gear if the left side of motor lifts then mount is broken. in reverse if the right side of motor lifts then that side is broken.
 

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A loose header can make just the noise you are describing, ask me how I know :clonk:
 

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Discussion Starter · #4 ·
I will check the header bolts ASAP thanks. I should have also noted that when accelerating and the noise happens the power cuts out at least partially..
 
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