1979 ford f250 460 knock??


Asked by Jul 08, 2015 at 04:47 PM about the 1979 Ford F-250

Question type: Maintenance & Repair

Hi guys, i have a 79 f250 with the 7.5 v8 that has been modified. Just today the engine
started making a knock sound. Its fairly loud and every time i give it throttle it gets
louder and faster and comes close to stalling. The truck has been sitting for about a
month or so due to some electrical issues (electrical fires) and a bad starter. I finally
got it back up and running good today and when i went to pull out of my shop it started
making the noise. It could be the gas from just sitting. It sat almost on empty. I dont
think it would be spark plugs because its ran fine up untill now. Within the past few
months ive ran 2 or 3 bottles of fuel additive through it. Any ideas or comments are
much appreciated. It was my great grandpas truck he bought in 79 and he modified it
fairly heavily. Im pretty sure he put a cam, edelbrock 4 barrel carb, intake manifold,
lifters, and 429 heads on it. Thanks for the help!

3 Answers


get a long screwdriver ,broom handle...place it on each exhause port and to your ear and listen with it running.....if one is more pronounced pull that side valve cover off and look for anything funny.if all is ok....next thing drop the pan..

1 of 1 people found this helpful.

this is a video to help what it sounds like https://www.youtube.com/watch?v=SzLW2pM_e_k&feature=youtu.be

1 of 1 people found this helpful.

exhaust leak, or dropped a valve is what pops in my head from what I read about it.

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