What does detonation sound like?

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lemondana said:
I had a classmate back in high school that got a 1973 Gran Torino Sport with the 351 4 barrel Cleveland. He had a lot of money and had his engine "built" , put I think 12.5 to 1 compression pistons, the biggest hydraulic cam that was available back then. He had headers and sidepipes put on it. He left the transmission stock and had 3.00 gears in the 9" rear end. Then his high school sweetie got knocked up and she was driving this as a daily driver. Mind you- this was right when they did away with Premium gas, right around 1975. She pulled into the small town gas station, where we were standing in the open bay door. She filled up with regular, we yelled at her to get on it when she left. It was the most horrific detonation I had ever heard. Like large marbles getting thrown in a big coffee can. Yeow!
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Ugh. The Cleveland was, according to my Mopar Performance Engine book ( 1991 edition) was The ONLY motor w/ heads that could outflow (CFM wise)the 426 Hemi. Mopar or No Car!, but that sucks to hear that.
 
Quick update. This morning I went over everything we discussed checked the air gap in the dizzy it was way too much set it to .008. Changed the plugs the ones in it was very black and sooty I had one that looked different from the rest it was black but almost seemed wet didn't look like oil tho. Checked my firing order it was good. After that I fired it up and took it out its running WAY WAY BETTER! it still has a slight stumble when I straight up floor it from a dead stop but if I kinda lean on it and ease into full throttle its fine. I floored it at around 10-15 mph (I don't have a speedo atm) and it left two black marks about 30 foot long. Its running better still gotta tune that stumble out of it tho. Good news is no more backfiring or falling on its face when I give it gas. On one test run I got it up to about 5k rpms man this is scary up there I've never owned anything that runs like this. Its only gonna get better once I get it tuned right.

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clementine said:
Im still waiting for a video:poke:
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I’m thinking posting a video of my own might be helpful in my thread I’ve got going with a similar issue. It’s hard to describe the sound, and for all I know with my untrained ear, it could be a lean misfire or detonation.
 
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