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KC John

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Kansas City
First Name
John
Truck Year
1974
Truck Model
C20
Engine Size
5.7L 350
Roger that @Catbox In case its not obvious, I'm not on any forums. And don't do Facebook or anything. I'm picking up the need for pics from other threads I'm reading here. I checked my phone to put some out and am realizing I only have videos! Mostly of my son test driving it around the lot after our infrequent successes. Truck is inside now but I'll definitely grab a shot or two to put out here. Thanks!
 

OldBlueDually

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Minnesota
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Justin
Truck Year
1976 GMC
Truck Model
C30
Engine Size
455 Olds
Welcome from Minnesota!!

I was gunna mention if its a Q junk that the inlet filter may be clogged. Thats where i was heading.

Whoaaaa that hurts man :D Q-junk :hmm: I personally love those carbs, and when you know how to re-build them correctly (I am still learning, my dad is a master at it), they perform awesome!

I have run Q-Jets on most of my engines, and will be building one for my 455 Olds for my 76 GMC.

To me they also have a distinct sound to them when you get on it. I love the violent acceleration that happens when you nail them while driving (split second between normal operation & mechanical 4-bbls opening), and that huge vacuum sound from under the hood, and all those American horses singing...
 

82sbshortbed

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Doug
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1500 shortbed, 1500 longbed
Engine Size
454, 305
I would keep the quadrajet if it was me. I've got one on my BBC 454. It had a edelbrock 1407 on it before. Junk imo. Gm put the quadrajet on it for a reason. It's the better carb. People will argue with that but, I still think it's the better one.

If you don't want to rebuild it yourself then there's a guy called the mountain man in Arizona I think that if you mail it to him will charge about $250 to do it.

Or you can call national carburetor or go to their site and get one for about 50 bucks more. That's what I did. I called them and told them what I wanted and he was really nice and had lots of good info on them. Very nice people.

It was about $330 shipped to me from Florida. They have all different types of carbs. They're the biggest carb dealer around.

https://nationalcarburetors.com/?gc...lZqqfBgETWpYoy3RrBCzBa49wUXJjKbRoCWCUQAvD_BwE

I was really happy with mine. It's just as good as new. I slapped that baby on and it fired right up and ran way better that that ****** edelbrock one did. They tune it for you so all you have to do is put it on. Hope this helps.
 

78C10BigTen

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pennsylvannia
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Ted
Truck Year
1978
Truck Model
C10 BIG TEN
Engine Size
350
Welcome from Minnesota!!



Whoaaaa that hurts man :D Q-junk :hmm: I personally love those carbs, and when you know how to re-build them correctly (I am still learning, my dad is a master at it), they perform awesome!

I have run Q-Jets on most of my engines, and will be building one for my 455 Olds for my 76 GMC.

To me they also have a distinct sound to them when you get on it. I love the violent acceleration that happens when you nail them while driving (split second between normal operation & mechanical 4-bbls opening), and that huge vacuum sound from under the hood, and all those American horses singing...
Ive never used one, mine was swapped to an eddy before i got it so i have no idea. I just call it Q junk as thats what ive always heard it refered to as.
 

KC John

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Kansas City
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John
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1974
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C20
Engine Size
5.7L 350
@Catbox We have to keep her parked in the shop for now, but I snapped a quick shot and put it as my profile pic (or whatever)

@82sbshortbed I will definitely give the nationalcarb thing a look. I think I've seen that other places sell rebuilt ones, but it's good to have a recommendation. Thanks
 

78C10BigTen

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Ted
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Engine Size
350
@Catbox We have to keep her parked in the shop for now, but I snapped a quick shot and put it as my profile pic (or whatever)

@82sbshortbed I will definitely give the nationalcarb thing a look. I think I've seen that other places sell rebuilt ones, but it's good to have a recommendation. Thanks
Looks like a good truck! I always loved that inset grille.
 

KC John

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Kansas City
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John
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1974
Truck Model
C20
Engine Size
5.7L 350
Looks like a good truck! I always loved that inset grille.

Thanks, we're fond of it. Hopefully we can get it back on the road and then it'll be even better. There's a truck driver that picks up from us on occasion and the grill is the thing he always comments on.
 

Grit dog

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Auburn, Washington
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Todd
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454, 350
Welcome KC!

Im not a Qjet expert. Haven’t even touched one since the early 90s, but check the simple stuff first.
Once warmed up, is the choke off and fuel pump still making fuel?
Is it fuel or spark related?
If you determine it’s the carb there’s plenty of people who are very familiar with them here.
I wouldn’t be afraid to get a rebuild kit and try rebuilding it though. $25-30 only. Just be meticulous about how you disassemble it.
Good luck. Truck looks cool!
 

SquareRoot

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Arizona
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Mike
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85
Truck Model
K20
Engine Size
350
Welcome, I'm Mike. My typical response is usually "shitcan it, LS swap." However, you never said your motor was bad. Therefore, shitcan it, Pro-flo4 EFI it.

Carry on
 

OldBlueDually

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Minnesota
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Justin
Truck Year
1976 GMC
Truck Model
C30
Engine Size
455 Olds
Ive never used one, mine was swapped to an eddy before i got it so i have no idea. I just call it Q junk as thats what ive always heard it refered to as.

Ah, I see. So you have never really had a real carb :eek: :anitoof: Just givin' ya some crap!
 

oldretiredafguy

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N. Texas
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Mike
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1988, 1988, 1991, 1983
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GMC V-Jimmy, GMC Suburban 4WD, GMC Suburban 4WD, GMC-2500 CrewCab
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350, 350, 350, 350
Welcome from N. Texas!

You must be registered for see images attach


I like to keep things simple. I would just bet that after all the years since the truck came off the line, the bottom of the fuel tank(s) looks like the grease trap in a fried chicken joint kitchen. Not fun to clean out, but a necessary evil in the world of vintage vehicles.
 

75gmck25

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Northern Virginia
First Name
Bruce
Truck Year
1975
Truck Model
K25 Camper Special TH350 NP203
Engine Size
5.7
The OP mentioned swapping fuel filters a couple of times, but later said he has hard line from the fuel pump to the carburetor.

So which fuel filter are you’re replacing? The one in the carb inlet is easy to replace if the fitting still has good threads (many folks seem to get it cross threaded), but you need to get the spring and filter back in correctly. Do you also have an aftermarket filter in one of the rubber lines?

It sounds like it would be beneficial to rebuild the carburetor. However, you might get by for now with just ensuring all the vacuum ports are hooked up correctly (or plugged), verifying the accelerator pump works, and setting idle mixture and idle speed. Also check the operation of the choke, especially that it pulls off completely when warm. Use a spray can of carburetor cleaner or WD-40 to check for vacuum leaks at the carburetor base gasket.

Bruce
 

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