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355 Weird Noise

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Old 05-04-2015, 08:25 AM
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355 Weird Noise

Hey everyone so i have a 85 trans am with a 355 in it. I was driving on the highway yesterday with her, and all the sudden she started running very poorly. So i pulled over and had her towed. I cannot figure out why she started running so poorly out of the blue.

https://www.youtube.com/watch?v=ciNQ...ature=youtu.be

Shes a 350 bored over .30 to a 355. A mild hydraulic roller camshaft. A pair of aluminum heads, brand was not specified. Edelbrock RPM performer intake. Holley 770 street avenger. I have a build sheet on it if you need more specific information.

Some back story, I just bought her about a month ago. The transmission blew about 3 days into my ownership. So after getting it performance rebuilt and installed by my local performance shop. I drove her around for a good week. Now i know the engine needed to be turned, cause she would back fire sometimes, when you would go to turn the car off.
Old 05-04-2015, 08:54 AM
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Car: '90 Camaro
Engine: 305 tbi
Transmission: T5
Axle/Gears: 9 bolt posi 373
Re: 355 Weird Noise

Need to be a little more specific on this weird noise and where exactly it's coming from. Not tryin to sound mean
Old 05-04-2015, 09:19 AM
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Re: 355 Weird Noise

Directly in the block don't really have an idea
Old 05-04-2015, 11:28 AM
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Car: 1986 IROC Z28
Engine: Carburated small block 454
Transmission: Level 3 Raptor 700R4 2600 stall
Axle/Gears: Strange S60 3:73 S Trac Posi
Re: 355 Weird Noise

Can't tell much from the video, you are going to have to do some trouble shooting to know what's happened. I'd start with a compression check and then pull the valve covers looking for bent push rods or anything else out of wack on the heads. Check the timing marks to see if it's jumped time; if it has, you probably have some bent valves and will need to have the heads reworked.
Old 05-04-2015, 12:49 PM
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Car: 90 formula, 89 formula 350 vert
Engine: 305, 355
Transmission: T5, t56
Axle/Gears: 3:45 9 bolt, 8.8 3:73
Re: 355 Weird Noise

sounds like a valve train issue if this happened all of a sudden and caused rough running. Pulling the valve covers will be the first step. You may find the cause right away or after a little looking such as broken valve springs, pushrods,etc.
Old 05-06-2015, 01:01 PM
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Re: 355 Weird Noise

Found out a valve snapped
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