Novice needs suggestions for new/rebuilt carb

[Erik]

Hey all. Does anyone have suggestions for a new or rebuilt carb for my truck? I am out of my element here. The truck is a 1974 C20 with a 350, all stock. The current carb is a Quadrajet off a 1975 with the divorced choke with the old-school coil spring mounted on the engine - the carb was rebuilt by Holley at some point. Pics attached. I've had the truck for about 5 years and it has always run great, but recently it started hesitating/bogging down when accelerating and idling poorly (like it wants to die). The hesitating/bogging issue seems to have solved itself (or I solved it accidentally), but it is still idling poorly. I got a vacuum gauge and tried to adjust the idle mixture, but no improvement. My mechanic believes it is a fuel issue rather than ignition-related. The fuel filter is new, spark plugs are new. I could change the wires and distributor cap and see if that helps at all - probably needs new ones anyway.

The current carb is filthy and probably needs a rebuild, but Lars Grimsrud in Colorado - who come highly recommended - told me the previous Holley rebuild will make it impossible for him to rebuild it economically, and commercial rebuild services seem to take many weeks or months to rebuild - and this is my daily driver. Therefore, I think my best/quickest option is to buy a new or rebuilt one so I can get it fairly quickly.

Which leads me to... What would you do (other than rebuild it yourself, which I don't have the time to do at this point). I could look around for a rebuilt Quadrajet from around my model year with the same choke style to make things easier. If I do that, can anyone recommend a source that does decent rebuilds? Holley, Edelbrock, etc, I've heard about but just don't have the knowledge.

I'm just a novice who needs some guidance here. I do not want to or know how to do a lot of tuning - I just want something I can bolt on that will run OK. Thanks for the help.

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[Erik]

Also, if I get a carb with a different style choke, is that going to make it hard for me to put the new one on?

 

[Snoots]

Cliff Ruggles.
Get ALL the specs on your engine that you can; cam, compression and rocker ratio, and the carb number. If it's all stock the first part is easy. The carb number is on the body behind the throttle. Get all the numbers.
Call Cliff and tell him what you have and need a kit. Buy his book. Read it. In the long run it'll make things a LOT easier.
Cliff does do rebuilds but he's backlogged months.
Don't forget to check out the GMSB Tech Section. Loads of valuable info there. Of course we're here to help too.
BTW, nize lookin' truck!

 

[Paladin]

Get a HOLLEY!!!! Cheers

 

[Erik]

Thanks!

 

[75gmck25]

It’s possible to rebuild and adjust the Quadrajet, but as you have found, it’s hard to get someone to a timely repair these days. I rebuilt my own with a kit from Cliff Ruggles a few years ago and IIRC the kit with quality parts was in the $200 price range. And then I had to buy a container of cleaning solvent big enough to immerse the carburetor. I also bought the kit to install new throttle shaft bushings, and converted to an electric choke. By the time I got done it was not a cheap rebuild.

If you have the cash, I would highly recommend trying the Edelbrock AVS 2, based on multiple recommendations I’ve found. It’s much improved over the old Edelbrock Performer carb and apparently has great off-idle performance. The only catch is that it’s a square bore carburetor and your intake might only accept a spread bore carburetor unless you buy an adapter.

 

[BlueMule]

Hey Eric, some facts regarding the much maligned non electronic Q Jet.

After 1972 the QJet would flow 800 CFM, more than enough to feed most street engines. It is funny how many folks will trade an 800 cfm QJet for a new Holly 600 cfm, go figure.

The spread bore configuration will get far better fuel mileage, especially in town than any spread bore, with no loss of power at the top end.

Cadillac used it on their 500 CuIn torque monster and Pontiac on their 455. Mercedes used a suspiciously QJet looking Solex 4 BBL Carb on their early '70s 4 door land yachts.

So with all this in mind, I agree with both '75, and Snoots, I have purchased from Cliffs and the kits and parts are the best available today. Cliffs is the best source for QJet stuff. Get the book, and make sure the idle wells are squeaky clean.

Get the HP kit, the book, and the choke pulloff, replacing the pulloff while you have the carb off now saves headaches later. The HP kit comes with the removable plug allowing you tweak the power valve to smooth out tip in transition, the accelerator pump is Ethanol Resistant "proof", etc. here are some linkies.

Quadrajet Rebuild Kits – Cliffs High Performance Quadrajets

Choose Your Quadrajet: Number Identification Guide

The Quadrajet carburetor has been used for decades, and we show you how to identify each variation. Find out what's sitting on your shelf.

www.chevyhardcore.com

BlueMule

 

[potent rodent]

have u ever changed the fuel filter

 

[WebMonkey]

i bought a rebuilt qjet off ebay.
bolted on and never looked back.

as for going to an electric choke version;
you just need to run a wire to supply power to the electric choke.

my 350 is from a '69 k20/30 and has the divorced choke intake but has an electric choke carb on it.

still had the 'temp unit' screwed on but not linked, till i removed it from the intake.

good luck

 

[Bennyt]

I'd stick with a quadrajet first and foremost!

There is a Quadrajet guy near me that is 1-2 weeks and he has plenty of cores. All carbs are run/ tested on stand. I assume he ships as his reviews are from around the country.

If interested, I'll get you his info tonight/ tomorrow as I am at work.