What should I look for in a good Qjet core? After sifting through numerous Qjet threads it appears the Qjets that are commercially rebuilt are nothing more than paper weights.
I'm trying to find a Qjet for a 454 w/ air conditioning that can be rebuilt. I'm not concerned with matching numbers. I'm not sure what a good rebuildable unit would look like or what to look for outside the obvious (cracks, inappropriate fuel line inlet for a Chevy)

I'd like to ditch the Edelbrock w/ the stupid adapter plate and go back to original.
I'm trying to avoid buying an old Qjet and it being trash that's unusable.

 

Contact Lars....He can look at pics and tell you if it's worth building or not.

Brian

 

Lars will send you some good information to help you find a carb that’s suitable and a listing of the Rochester carbs with applications.

 

Contact this guy...... https://www.corvetteforum.com/forums...uadrajets.html

I bought the "204" small block carb and it was a perfect core.......the other one he has is a "200" 454 carb. $100!

Jebby

 

What you want are Q-Jets which have been removed and have NEVER been rebuilt by anyone. Some ads will state that (i.e."carb was removed from engine and stored as-is"). And, if you know enough to make judgement as to proper carb configuration (per the P/N), you should have a good one to work on. If you find some 'candidates' for your project, you might send that info to Lars at V8FastCars@msn.com and ask him which HE would choose (if any of them).

Good luck........

 

If I’m building a carb for a motor, I’d rather use a late 70’s setup. They have all the reliability enhancements in place, plus you have an easily controlled APT setup. You may need to tweak the fuel line a bit, as the inlet location is slightly different on an M4M(75+) vs a 4M.

I had a 17058228 that was well set-up for my 400ci small block and it ran great.

The late 70’s carbs are easy to add A/C to, they all have the casting bosses to mount the kickup solenoid to. The only real trick is auto vs manual.

 

Has anyone had difficulty fitting the dual snorkel air cleaner over a Qjet outfitted with an electric choke?
I have the Edelbrock wired up as it is for electric choke so I'd like to keep that, but if I needed to go back to the original style choke its no big deal. Houston winters consist of about 5 days where a choke might be necessary.

I will see what Lars thinks on a few Qjet samples I've come across.

 

I used an M4M converted to electric choke, but that was with a 75-81 style intake. I used it with the single and dual snorkel variations. It worked fine. I don't see why the divorced electric choke wouldn't work.

 

Did you contact the fella I posted? He still has it......for $100 it is worth it to me and like I say.....the other one I bought from him was damn near perfect.

Jebby

 

Try looking at the local car shows with swapmeets. I never pay over $10 for a q-jet whether usable or rebuildable. Last time I inventoried I had 15 q-jets. Pay less for junk q-jet carbs but can use them for parts on others.

 

Yes. That is exactly with the bulk carb rebuilders do. Tear them down and use parts from 'this' for pieces to 'that'....which is OK IF you know which parts are compatible with the others. Whenoriginally manufactured, these carbs would have had an anticipated life span or 5 years, or so. "Rebuilding" a carb was done by the owner or by a local carb repair shop who ONLY replaced worn parts with new. Rochester never designed their parts to be interchangeable from model year-to-model year. Improvements were made continually--even during the model year and built carbs were conceived to stay together as a unit (except for worn or damaged parts) and for "like" parts to be found and substituted when such parts could not be reused during a rebuild process. Mix & match of random major carb components was not even a consideration when these things were designed or originally built. Today, the rebuilders just zip them apart and throw airhorn pieces in this bin and throttle plates in that bin...wash them, then make them available for rebuild. No wonder the rebuilt vendor products rarely work properly. Most all of them are Frankenstein carbs.....

 

Yes, you have to be VERY careful with this. You will probably be able to get away with somethings inside a carburetor family, but year over year changes make things difficult. APT changed 2-4 times through the 4MV years. There will be different baseplate and main body configuration in a single model year. The vacuum port for distributor vacuum may be manifold or ported depending on which engine configuration the carburetor was designed for for that model year, even though the port is visually identical from the outside of the carburetor. Using a main body from one and throttle body from another could end up with that port having one of the following symptoms: blocked port, unexpected vacuum signal, vacuum leak. And that's just one port. There are maybe 20 passages that connect between the main body and throttle body, and fewer, but still quite many between the air horn and main body.

You can typically get away with swapping quite a few hard parts (throttle shafts, secondary springs, air valve springs, air valve doors, throttle blades, metering rods, metering rod hangers, power pistons), but you absolutely need to know what you're doing. I'd shy away from swapping the major components at all, unless you are 100% sure you're like for like on parts.

 

I sent him a message a while ago.

 

No, I didn't specify which parts interchange. Yes q-jet bodies would have limited interchangeability. But many good reusable parts can be had for bargain prices. Metering rods is mostly what I had in mind but throttle blades and shafts are fair game. You would need to compare linkage arms for reuse.

Yes you need to use your brain before swapping q-jet parts.

 

Hey TexVette,
Just replied to you message. Sorry for the delayed reply, it was a busy weekend. I would say the 200 core I have is equally as good as the one I sold to Jebby. This one just might need a bit more tuning. The previous owner of my '80 stuck this 454 carb on my stock 350 that was on its last leg. It ran ok, but definitely wasn't tuned well for the car. I have no idea if any rods or jet were changed, but it was definitely rebuilt recently so its possible. That being said, it doesn't look like any of the bleeds have been messed with our drilled out. So I still think this would be a great core.

 

$100 for a GOOD and complete core unit and less than $50 for the rebuild kit and [maybe] float is a bargain compared $300+ for a 'questionable' rebuilt Q-Jet or even a "new" Edelbrock carb. But, the OP has to see the value in that approach. (No question, in my mind....)