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Hey, I have a 74 f250 with a 390, and I keep hearing this knock almost every time I drive the truck and its driving me insane. It only starts when I'm on a long run (1-2 miles) going around 50-65 at around 1k-1.3k rpm and it will knock until i sit at a light for a minute
or so. It is rpm dependent because when i put the clutch in it will die out like the revs will but it is still heard. I pulled the plugs on 1&5 and #1 looked very lean and #5 looked great, I have messed with the timing both ways but it didn't seem to change anything. I have also changed the fuel filter, but to the same result, no change. I took a quick video last week when I was on my way to school;
, This time it was not as loud as I've heard it but definitively noticeable.
Thanks,
Keegan Hall Here's my carb and intake setup, since this picture was taken I have changed that crappy fuel filter and the filter on the fuel pump. Btw I have a 160 degree thermostat installed.
