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#26 |
Registered User
Join Date: Mar 2013
Location: Campbellsville, KY
Posts: 888
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Re: Need carburetor suggestions for 283ci
Is the 4* timing the correct spec for your '67 engine? That sounds too low for a pre-smog engine but I may be wrong. I'd bump it to 8 or 10 before I did much more with the carb.
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Alex V. ------ 1967 C10 Suburban, 350/NP435, Green/Green, PS, PB, HD cooling, charging, shocks, and springs. 1985 GMC C3500 SRW, Sierra Classic, 454/TH400, white/blue. |
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#27 |
Registered User
Join Date: Jul 2002
Location: St. James, MO
Posts: 1,239
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Re: Need carburetor suggestions for 283ci
I have been running one for over ten years in my K10 on my 327. I have no complaints. I *prefer* a really good, well-tuned Q-jet, but I haven't the patience or the time do tune one or the money to have someone else do it.
__________________
'69 Longstep K-10: 327/SM465/T-221/Closed Knuckle Dana44/12-bolt. |
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#28 |
Registered User
Join Date: Jun 2015
Location: Bellevue, Id
Posts: 173
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Re: Need carburetor suggestions for 283ci
Yes 4*btdc is the correct spec from the book.
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http://67-72chevytrucks.com/vboard/s...25#post7532025 71 Cheyenne K10. 283/Th350/NP205. 3.07s non posi. 31x10.5 Bighorns.L31 350 Vortec swap in progress. 79 Suburban K20. 350/350. 6" lift. 35x12.5 Toyos. 93 Burb K1500. 350/4l60e Parting out. 2001 Tahoe LT, 5.3, autoride, 265/75s, leather, loaded, family hauler, 243k miles! |
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#29 |
Registered User
Join Date: Dec 2013
Location: northwestern PA
Posts: 54
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Re: Need carburetor suggestions for 283ci
I did a little research when I put the Q-jet on my 283 Malibu and as far as I could find no 283 ever came from the factory with a Q-jet. Apparently Q-jet production started within the last year or two of 283 production and the few 4 barrel 283's produced during that time frame all came with the 4G. As far as i could find the smallest small block that came with a Q-jet was the 305. That is why I had Cliff do my Q-jet, i figured if anyone could make it work, he could. I was looking for fuel efficiency since the Malibu is a daily driven commuter, but still a little power for towing. It has accomplished those objectives. The only indication that it is a large carb for the application is that even with the idle speed adjustment screw all the way out it still idles about 50 rpm higher than i would like. Apparently the idle circuit is too large to feed that little 283 at idle.
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#30 |
Registered User
Join Date: Jun 2015
Location: Bellevue, Id
Posts: 173
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Re: Need carburetor suggestions for 283ci
Here is the intake number as far as I can tell 388 or 3980364. I can't find it anywhere on the net . I will take a wire wheel to it this week and get an updated picture up.
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http://67-72chevytrucks.com/vboard/s...25#post7532025 71 Cheyenne K10. 283/Th350/NP205. 3.07s non posi. 31x10.5 Bighorns.L31 350 Vortec swap in progress. 79 Suburban K20. 350/350. 6" lift. 35x12.5 Toyos. 93 Burb K1500. 350/4l60e Parting out. 2001 Tahoe LT, 5.3, autoride, 265/75s, leather, loaded, family hauler, 243k miles! |
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#31 |
Registered User
Join Date: Apr 2010
Location: So Cal
Posts: 1,441
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Re: Need carburetor suggestions for 283ci
http://www.carbkitsource.com/carbs/t...jet-index.html
Read DESIGN on the left. .....The basic 750 cfm QJet casting is used from 231 CID to over 400 CID -
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'67 GMC 2500, 292, 4spd, AC |
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#32 |
Registered User
![]() Join Date: Nov 2006
Location: Virginia's Eastern Shore
Posts: 91
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Re: Need carburetor suggestions for 283ci
Seems to me that you're not quite ready to pitch the QJ just yet--------here's a link to to a large chunk of info on 'em (didn't see it mentioned). Lars used to rebuild carbs for forum guys but stopped the practice quite some time ago. This article is a bit dated but still very informative:
http://www.corvette-restoration.com/...arb_Tuning.pdf .......and another one that presents problems/issues: http://www.corvette-restoration.com/...leshooting.pdf |
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#33 | |
Registered User
Join Date: Mar 2013
Location: Campbellsville, KY
Posts: 888
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Re: Need carburetor suggestions for 283ci
Quote:
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Alex V. ------ 1967 C10 Suburban, 350/NP435, Green/Green, PS, PB, HD cooling, charging, shocks, and springs. 1985 GMC C3500 SRW, Sierra Classic, 454/TH400, white/blue. |
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#34 | |
Registered User
Join Date: Sep 2011
Location: Ark City, Kansas
Posts: 3,339
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Re: Need carburetor suggestions for 283ci
Quote:
Thanks! |
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#35 |
Registered User
Join Date: Dec 2013
Location: northwestern PA
Posts: 54
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Re: Need carburetor suggestions for 283ci
Will do. May take me a day or two to get to it. Randy.
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#36 |
Registered User
Join Date: Dec 2013
Location: northwestern PA
Posts: 54
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Re: Need carburetor suggestions for 283ci
68Gold,
The secondary air flaps on my Cliff-built Q-Jet easily open to the fully open position. Hope this helps... Also, I found some of the specs for this carb; Jets are 066 Primary Metering Rods are 39 Remember this is set up for an intermediate size car for fuel efficiency. Results likely will vary for trucks. |
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#37 | |
Registered User
Join Date: Sep 2011
Location: Ark City, Kansas
Posts: 3,339
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Re: Need carburetor suggestions for 283ci
Quote:
Cliff is the Q-Jet man! I am putting the 283 from my 67 Bel Air into my 67 C-10 hopefully this summer. I had this engine professionally built in 1984, and dyno'd. It's just a daily driver. I didn't have the info back then to properly build a Q-Jet back then. Tried several, didn't do well. |
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#38 |
Registered User
Join Date: Jun 2015
Location: Bellevue, Id
Posts: 173
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Re: Need carburetor suggestions for 283ci
So it's been a while since I was on the thread. I've been messing around with the Ole qjet and have gotten it to run quite a bit better. I started noticing upon closer inspection that it has been frankensteined. 2 check balls for the accelerator pump passage. A modified power piston spring and a set of primary rods with no stamp. I replaced the spring with another I had laying around and put in a set of 39b rods as well as removing the extra check ball. It has no more part throttle hesitation or off idle stumble but still has wot hesitation. Overall it's a huge improvement but I'm getting about 6mpg now. I'm not sure the jet size but that's where I'm headed next. I would live to find a complete spec sheet for 283ci qjet setup i.e. jets, rods both primary and 2nd, springs hangers, etc..
__________________
http://67-72chevytrucks.com/vboard/s...25#post7532025 71 Cheyenne K10. 283/Th350/NP205. 3.07s non posi. 31x10.5 Bighorns.L31 350 Vortec swap in progress. 79 Suburban K20. 350/350. 6" lift. 35x12.5 Toyos. 93 Burb K1500. 350/4l60e Parting out. 2001 Tahoe LT, 5.3, autoride, 265/75s, leather, loaded, family hauler, 243k miles! |
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#39 |
Registered User
Join Date: Mar 2013
Location: Campbellsville, KY
Posts: 888
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Re: Need carburetor suggestions for 283ci
I believe it's been determined there really isn't an established spec sheet for a 283 Quadrajet application. Oldchevynut's specs should be a good starting point, though I think jetting needs will more depend on the exact engine setup (head type, compression ratio, etc.) than what vehicle it's setting in.
If it was mine I'd get it set up real close to oldchevynut's specs and make any further adjustments based on the traditional methods - spark plug color, vacuum, throttle response, etc.
__________________
Alex V. ------ 1967 C10 Suburban, 350/NP435, Green/Green, PS, PB, HD cooling, charging, shocks, and springs. 1985 GMC C3500 SRW, Sierra Classic, 454/TH400, white/blue. |
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#40 |
Registered User
Join Date: Jun 2015
Location: Bellevue, Id
Posts: 173
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Re: Need carburetor suggestions for 283ci
Thanks. I'll look into it. Mines stock setup w power pak heads. Which I think came on it. I'll update when I get a little closer to where I want it.
__________________
http://67-72chevytrucks.com/vboard/s...25#post7532025 71 Cheyenne K10. 283/Th350/NP205. 3.07s non posi. 31x10.5 Bighorns.L31 350 Vortec swap in progress. 79 Suburban K20. 350/350. 6" lift. 35x12.5 Toyos. 93 Burb K1500. 350/4l60e Parting out. 2001 Tahoe LT, 5.3, autoride, 265/75s, leather, loaded, family hauler, 243k miles! |
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#41 |
Registered User
Join Date: Sep 2011
Location: Ark City, Kansas
Posts: 3,339
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Re: Need carburetor suggestions for 283ci
Cliff can give you what you need, parts or info. wise.Get his book, Hastings or Barnes and Noble usually has it on hand, he sells his book, also...
His tuning ability is huge, not just his Q-Jet knowledge, either... Get the carb tailored to your engine, you'll be smiling!!! |
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#42 |
Registered User
Join Date: Mar 2016
Location: Midlothian, TX
Posts: 55
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Re: Need carburetor suggestions for 283ci
On your Q-jet. If it bogs on full throttle acceleration for a second but then kicks in, your vacuum secondaries are opening too fast. Usually really easy to fix. A Small allen screw to adjust the secondary's make them slightly tighter. it can stop that bog pretty much every time.
http://www.73-87.com/7387garage/driv...lock_screw.jpg
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1970 GMC Stepside Short Gone...Factory 350 V8 Now...4.8L LS |
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#43 |
Registered User
Join Date: Jun 2015
Location: Bellevue, Id
Posts: 173
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Re: Need carburetor suggestions for 283ci
The bog I'm talking about is more of a constant at wot. Like a skipping.
__________________
http://67-72chevytrucks.com/vboard/s...25#post7532025 71 Cheyenne K10. 283/Th350/NP205. 3.07s non posi. 31x10.5 Bighorns.L31 350 Vortec swap in progress. 79 Suburban K20. 350/350. 6" lift. 35x12.5 Toyos. 93 Burb K1500. 350/4l60e Parting out. 2001 Tahoe LT, 5.3, autoride, 265/75s, leather, loaded, family hauler, 243k miles! |
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