Jets for a Q-jet on a 283

[67chevy2wd]

I put a Q-jet, the carb is off of a 76 350, now it is on my 283 and now i have to jet it down but can't find anywhere that can help me get a set of jets, and a set of metering rods.. I also i can't figure of which size jets i will need. There is a 69 stamped on the jets i have is that the size or just some number. I went to a Chevy dealer and they couldn't really help me because they didn't really know what to do either. I have to original 2 jet rodchester from the 283 can i just take the jets and rods out of that and use those or would those be too small. I had put a post on here before and was told it could be done but i can't figure out which jets i need so any information would be helpful. Thanks

[67chevy2wd]

i took the jets out of my 2 jet and found out that they have 54 stamped on them and i am pretty sure that they wont work so i don't know what to do now but also there wasn't any metering rods in the 2 jet. maybe someone has some idea about what size jets i would need.

[1972C10]

Seems like i remeber someone sayin that holley jets will work in a q jet but q jet jets wont work on a holley.

[67chevy2wd]

Thank, but will the holy metering rods work and you wouldn't happen to know what size i would need would anyone. but thanks that was a big help.

[1972C10]

I heard that from a local auto shop teacher and i think he sucks.

I tryed to jet my big block carb down that had 75 jets in it so i put some holley 70s in it and after putting it back together it ran good at idle put when put under rpm died

I then compared the jets i took out to some other holley jets and noticed that the stock q jet jets have a taper for the metering rod and the holleys do not so aparently this will not work.

If you find a place to get some jets or get some and want to get rid of your old ones id like to have some around 68 or 69

[tmad]

Got to do the same with my Q-Jet, Its from a big old olds rocket. I think its time to buy a Holley! Much more user friendly. I was told the Q-Jet is about 850 cfm my 283 only needs about 550-600 cfm so Im told.

[tom hand]

Edelbrock sells jets and metering rods for primary and secondary. 69 is next to the smallest jet they sell so you proably just need bigger metering rods. Go to edelbrock.com and look under q-jet accessories. If you could get in good with a Chevy parts guy, get him to look up what was in a 305 with a q-jet...that should give you a good starting point. Chevy was notorious for not even changeing jets...they would change the float level.....look at a rebuild kit instruction sheet and see how many different float levels they have for different engines,q-jets are super sensitive to float level changes...I wouldn't be surprised if you couldn't solve the whole problem by adjusting the float....maybe somebody on here has a sheet laying around and could help you out. What is the carb doing now? If the carb is in good shape and jetted for a 350...it should run ok.....just have crappy gas mileage and maybe a little black smoke...I don't think jetting would cause major problems like you described in an eariler post. Good Luck

[Bowtie67]

Have you guys tried running these before you try rejetting them because they came off of a bigger motor, I pulled one from a 350 4x4 and put it on my 283 and didn't have to do anything except adjust it. Here is a sight that specializes in Qjets, I did a lookup of quadrajet jetting kits..

http://www.carbs.net/quadrajet.asp

[67chevy2wd]

The engine idles fine but when u try and floor it it sputters and chokes. It also cracks or backfires when rev it from idle. If you hold it at like half throtle and floor it, it will rev up fine. When i floored it with out reving it up first and opened the secondarys it cut out and then it took off and reved up. I was just thinking that it was getting too much gass. I tried driveing just the length of my shop and it just died it has no power at all. It smokes really bad when u rev it up but i think that is just from the heads leaking oil into the cylinder. I was told that the old heads are bad for that especially in a high compression 283 and a high comression 350. I was also told that this card was a 795 if that makes much of a difference.

[Bowtie67]

Back firing when you tromp on it could be vacuum issue going to Distributer advance as well as accelerator pump or AP adjustment, also might be fuel adjustment, if the carb worked fine before putting it on you should be able to drive it as is without any major issues, as with any carb and changing jets, one should drive it at normal speeds or set RPM, we'll say 2000rpm for at least a mile or two after warmed up, shut engine down, do not let idle, pull plugs to check condition and adjust from there, never make primary and secondary jet changes at the same time. do one then the other to tune a carb. Tuning carbs is not the most fun thing there is, regardless of what ever brand you may have, The potential with a fine tuned Quadrajet is awsum I don't think an edlerbrock will ever come close to the performance capabilities of a QJet. Of coarse as many guys do, they buy new carbs that are pretty much jetted right out of the box and they claim how wonderful they are... JMO

[1972C10]

I ran mine it ran great just put out black smoke and had horrid gas mileage ..

I have a carb that came off a factory 454 and is on a 355