I recently added an electronic ignition and car rebuild to my 1972 F-100 (has a 302)

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The same day the engine developed a screeching noise that I have been unable to determine its origin. The truck ran fine for several hours and now along with this noise it will not idle and it seems that this noise is somehow related to this issue.

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I have changed all of the belts and still no luck.

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Any help or suggestions would be greatly appreciated.

Thanks

 

It sounds as if you have a big vacuum leak that may have developed when something on or around the carb was left off. Get a flashlight and slowly but methodically do a search for anything that looks like it may be a leak.

There is a quicker method involving an aerosol can containing a flammable liquid and a running engine, but it's not really worth the risk. I wonder if the same results could be had with a squirt bottle filled with water?

 

Cracked intake gasket. Use 390fe's method for checking.