fresh air intake

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Matt69olds

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I’m sure the air intakes are covered in the front to prevent large objects like big bugs, leaves, road debris, gravel, etc in addition to water from getting to the air filter. Having the air inlets open would be ok for probably 95% of the time, GM has to worry and design the trucks for everyone.

As for the air inlets being open, my 69 Olds has the OAI system. It’s 2 air scoops under the front bumper, with black cloth dryer hose looking hoses going to the air cleaner. I have found grasshoppers, straw, caterpillars, all kinds of crap in the air filter. Basically, the car is like a big vacuum cleaner! The factory included a brochure with winter instructions, basically telling the owner to disconnect the hoses from the scoops, and closing off the hoses with tape. I guess GM wasn’t concerned with rain, but snow and ice is a problem.
 

Craig 85

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I have cut the end off that cap on all 8 of my square body trucks. This is my current K30. The first 6 were my daily drivers at some point between 1989 and 2001 and never had any issues. You could always drill some holes on the underside of the tube for water drainage.

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Keith Seymore

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That's how I did my Chevelle (cut the birdcage portion off.

By the way - I designed the engine air induction system for the GMT800 model trucks (1999 model year introduction).

It was my first design job. Most of the pieces are still in use today.

K
 

bucket

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That's how I did my Chevelle (cut the birdcage portion off.

By the way - I designed the engine air induction system for the GMT800 model trucks (1999 model year introduction).

It was my first design job. Most of the pieces are still in use today.

K

That's cool. You did well on it, I like that there's no silly noises. And it's easy to pop out of the way for service.
 

Craig 85

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@Keith Seymore what was the purpose of the inner screen on 454 trucks? I had always heard this was for noise reduction.

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Backfoot100

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@Keith Seymore what was the purpose of the inner screen on 454 trucks? I had always heard this was for noise reduction.

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Not just for 454' s. I had that on my 350. I just assumed its a flash arrestor. Similar to what is Coast Guard mandatory on boats but this thing is far more restrictive. After I removed it I had a noticeable performance improvement.

There was a shorter and taller air cleaner available. I don't know that I ever saw one in the shorter versions but I'm certainly no expert. I have really no idea why or what determined what engines got the tall air cleaner vs. the shorter one.
 

Keith Seymore

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Agree. Flame arrester.

Noise attenuation happens with the tapered snorkel, or by all the tuned devices (Helmholtz Resonators and quarter wave tubes) hanging off the ductwork.

K
 

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