Home Forums Hunting & Shooting Hunter's Campfire 350 SBC Carburetor

First thing is check the Carb # & date code to see if it's original to the truck (or engine) if it is the calibration will be correct unless someones messed with it.. Then check for excessively worn throttle shaft bores by adjusting the idle speed to factory spec (or your liking)... If you cant get it to idle slow enough with the idle speed screw backed all the way out (throttle blades completely closed) it means too much air is leaking past the shaft bores and they will have to be rebushed... Next check for leaking jet wells by running the engine, Then let it set (without messing with it) overnight... Then (without starting it) get your eyeballs overtop the carb and look down into the primary bores (carefully open the choke plate if necessary)... Now open the throttle several times... You should see fuel squirting out of the accelerator pump discharge holes... If no fuel squirts (or some fuel but mostly air) you have leaking jet wells... You can verify which ones are leaking with soapwater and compressed air after carb disassembly... The fix is to drill or mill the secondary jet well caps out and replace with screw in plugs(with epoxy on the threads)... The primary jet wells (if leaking) can often be carefully restaked... Just putting epoxy over the jet wells never works for long as the heat and fuel loosens it... Your best source for quality rebuild kits, parts & info is Cliffs Q-Jets (Cliff Ruggles) in Ohio... He wrote the best book available on Q- Jets (and iv'e read em all)... I do my own carbs (with Cliffs technical assistance)... But you should expect to pay someone competent about $300 for a basic stock rebuild or as much as $5-600 for a rebushed & jetwelled, recolored & replated, performance tuned works Job... And it's worth every penny... They work fantastic!... Ya'll can keep your Fool injection...

First thing is check the Carb # & date code to see if it's original to the truck (or engine) if it is the calibration will be correct unless someones messed with it.. Then check for excessively worn throttle shaft bores by adjusting the idle speed to factory spec (or your liking)... If you cant get it to idle slow enough with the idle speed screw backed all the way out (throttle blades completely closed) it means too much air is leaking past the shaft bores and they will have to be rebushed... Next check for leaking jet wells by running the engine, Then let it set (without messing with it) overnight... Then (without starting it) get your eyeballs overtop the carb and look down into the primary bores (carefully open the choke plate if necessary)... Now open the throttle several times... You should see fuel squirting out of the accelerator pump discharge holes... If no fuel squirts (or some fuel but mostly air) you have leaking jet wells... You can verify which ones are leaking with soapwater and compressed air after carb disassembly... The fix is to drill or mill the secondary jet well caps out and replace with screw in plugs(with epoxy on the threads)... The primary jet wells (if leaking) can often be carefully restaked... Just putting epoxy over the jet wells never works for long as the heat and fuel loosens it... Your best source for quality rebuild kits, parts & info is Cliffs Q-Jets (Cliff Ruggles) in Ohio... He wrote the best book available on Q- Jets (and iv'e read em all)... I do my own carbs (with Cliffs technical assistance)... But you should expect to pay someone competent about $300 for a basic stock rebuild or as much as $5-600 for a rebushed & jetwelled, recolored & replated, performance tuned works Job... And it's worth every penny... They work fantastic!... Ya'll can keep your Fool injection...

If you can’t figure out a Q jet you better go with something new. They are a very simple carb.if the throttle body isn’t wore out a simple kit will fix it. They make a tool kit to fix the throttle body also. Way better street carb than a Holley with way better mileage. Edk

Said nobody ever, like fking.... ever.

Qjet is the equivalent of a mechanical computer for fuel. Rube Goldberg masterbates to qjet illustrations. It's the most polarizing carburetor in existence, haters and cult followers.

It's a lot of things, but "simplest" is the furthest word from the truth.

Damm ..I've did a dozen truck rebuilds...same pickle the op's in...

I wouldn’t dream of painting that truck. That would looks so good just clear coat the rust
That patina can’t be duplicated. Unless it parked on a pasture for 30 years

The TH 400 uses an electric kickdown switch, there is no tv (throttle vavle) cable... The TH 350 uses a kickdown cable (kicks trans into a lower gear for better acceleration) operated by the carb linkage... There is no tv cable on it either... TV (throttle vavle) cables were used on TH700 4r's and TH200 r4's in the 80's to control hydraulic pressure in the transmission...

And what route did you go?

I was fishing for a reaction from JC, he questioned of TH400 would be in there behind a sbc in a c10 so that sort of dead ended on me. No cable on th400.

You should come and fix one of my aluminum powerglides. It shifts super prematurely in drive and will not kick down. Does fine if shifted manually. I think it's a governor issue, thoughts?

Holly used to, about 45 years ago, offer a spread bore model as a direct replacement for Quadrajets. I had one and it worked beutifully. It was a 650 cfm as I recall and fuel economy just about doubled on a '70 model 300 hp 350.
Good Luck with your truck!
Rick

Opinions are often based on what you know. I rebuilt a lot of Qjets and other carbs when I was turning wrenches. The Qjet is my favorite.
Loco above has been into them as well by the explanation of the well jets. Spot on. Edk