77 fresh air duct

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lcfman

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Thanks for all the info I think I will order the duct from LMC. Another thing I was thinking about doing is enlarging the core support hole opening as on my truck it is about 75 % blocked at the hose attachment assembly . I don't know why GM closed off so much of the hole, maybe it was some sort of increased flow with the smaller opening. It seems to me a full hole would be better.
 

Snoots

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It would. But their brain was only half functioning.
 

Craig 85

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Here's something I've done with several of my trucks. I cut the opening cover off so it is more of a ram air affect. I done forge water, so that's not an issue and I've never had an issue with rain.

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Best truck design

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My 1973 Camper Special has no snorkels and we have owned it since it was 4 years old. (So they were never removed)
 

PrairieDrifter

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My 1973 Camper Special has no snorkels and we have owned it since it was 4 years old. (So they were never removed)

Is it an oil bath air cleaner? Cuz otherwise it should have had a snorkel on it.
 

lcfman

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Just a follow up. I bought the LMC fresh air hose for my 77 and it fits good and looks like a good piece. LMC offers 2 lengths and I bought the shorter one and as stated it fits as it should. Thanks for the input.
 

AuroraGirl

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Anyone know what the fancy box is for around the inlet? 80s i think core support.
 

Matt69olds

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Thanks for all the info I think I will order the duct from LMC. Another thing I was thinking about doing is enlarging the core support hole opening as on my truck it is about 75 % blocked at the hose attachment assembly . I don't know why GM closed off so much of the hole, maybe it was some sort of increased flow with the smaller opening. It seems to me a full hole would be better.


I bet they designed the hole closed off partially to comply with the drive by noise restrictions. With the ever increasing governmental pollution/noise/fuel economy requirements the Big 3 had (and continue to fight) its not hard to understand why cars and trucks started to get so expensive in the mid 70s.


The Pontiac Trans Am is a perfect example. In the early 70s, the shaker air cleaner was functional. Towards the late 70s the shaker was closed off to outside air and was cosmetic only.

The tapered air intake snorkel used on air cleaners was designed to quiet the fabulous roar of the Q-Jet. To me, that’s a required driving experience!
 

AuroraGirl

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I bet they designed the hole closed off partially to comply with the drive by noise restrictions. With the ever increasing governmental pollution/noise/fuel economy requirements the Big 3 had (and continue to fight) its not hard to understand why cars and trucks started to get so expensive in the mid 70s.


The Pontiac Trans Am is a perfect example. In the early 70s, the shaker air cleaner was functional. Towards the late 70s the shaker was closed off to outside air and was cosmetic only.

The tapered air intake snorkel used on air cleaners was designed to quiet the fabulous roar of the Q-Jet. To me, that’s a required driving experience!
79 coupe rare grille.. well half

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80BrownK10

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I need a engine fresh air duct that run from the core support to the carb air cleaner (round to oval). The only part I could find is from LMC and it for later years '80's model but none for '77. The one LMC offers looks like it might work but I am not sure. Anyone know who sells one?
I am useing a dryer duct on the setup I'm about to install on my 80. The air cleaner I have has an oval intake and the front core support duct is round. You can squeeze a 4" dryer duct to fit that oval intake. I got the black dryer hose off Amazon so it doesn't look so ghetto or like I am Peg from zip ties and bias plies spraying whole cans of canned consent into my redlined diesels.
 

river77

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Has anybody tried the 22" fresh air duct offered from LMC on a 77? I asked them if they thought it would fit but they won't give me an answer. My 77 came with one, there's a guy on eBay that sells them but he said he's out stock and doesn't have a clue when new ones will arrive
 

Rusty Nail

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I am useing a dryer duct on the setup I'm about to install on my 80. The air cleaner I have has an oval intake and the front core support duct is round. You can squeeze a 4" dryer duct to fit that oval intake. I got the black dryer hose off Amazon so it doesn't look so ghetto or like I am Peg from zip ties and bias plies spraying whole cans of canned consent into my redlined diesels.

That's good writing right there mmmhmm.
 

Craig 85

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Has anybody tried the 22" fresh air duct offered from LMC on a 77? I asked them if they thought it would fit but they won't give me an answer. My 77 came with one, there's a guy on eBay that sells them but he said he's out stock and doesn't have a clue when new ones will arrive
I ran into an issue with my '85. I purchased the one for my year truck, but it turns out the one they sell is for a small block. The angle at the snorkel was wrong making it a little short. I ended up cutting the end of the hose off near the core support and purchased this silicone tube from Summit to complete the connection.

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Royal Sierra 454

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Both of my 1976 C-15 454 and K5 400 came with snorkels. Both from CA. Maybe an emission thing? Both still have their original Flex duct.
 

AuroraGirl

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Both of my 1976 C-15 454 and K5 400 came with snorkels. Both from CA. Maybe an emission thing? Both still have their original Flex duct.
Wide or narrow snouts? Impressive tho. They were better for an engine overall
 

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