Problem with 350 chevy
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Problem with 350 chevy
A guy at work has a problem with his truck, its an 80s chevy with a 350 thats carborated. When ever he gets on the gas hard, either going up hill or on flat ground, it will backfire. He took it into a shop and they said its a flat cam, but he wants to make sure its not something simple before he does anything on it. It was rebuilt 5 years ago, has about 40,000 miles on it and I think he had a new carb installed. Any ideas?
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From: Redvers SK. Canada
Backfire in the exhaust, or through the carb? If it is in the carb, sounds like an intake valve or maybe the valves need re-adjusted. My brother and I bought an old impala with a 350 that was backfiring through the carb for 100 bucks. We then removed the valve covers and noticed the valves at the right rear bank, #6 & #8, were barely opening. So we knew the cam was going flat, a very common problem in chev's. We then adjusted all the valves to zero preload then half a turn down on the rocker nut. The old girl quit the backfiring and ran better, however the cam was still done. It then proceeded to be demolishin derbied!!!!!
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From: saskatoon,sask
i had a 76 camero 350 that when you hit high rpms it would pop back through the carb when i pulled the cam it was almost completely lobeless
has it just started doing this or ever since he rebuilt it.
has it just started doing this or ever since he rebuilt it.
Hotshot
Joined: Feb 2004
Posts: 11,697
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From: Marengo, Iowa
Another possibility is simply a vacuum leak or bad accelerator pump. The late 70's and 80's Chevy's had problems with the cams going flat as they were not hardened. Once the outer part of the cam wore down, they hit the soft metal inside, and wore down to what looked like a wheel on the cam... The bright idea behind this was to reduce valvetrain noise... Had a 454 wear a cam down in 400 miles once, after it had worn through the outer hardened metal. Had a Pontiac 350 do it too...
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