Need carburetor suggestions for 283ci

[chefk85]

I have been fighting issues with a 1977 qjet for months now. every mechanic I take it to adjusts it or rebuilds it and tells me its as good as it can get. I'm finally to the point I believe them. What would be the definitive answer be when it comes to this problem? I am in the market for a new carb but am having trouble figuring out what to get. Id hate to order one only to find its the wrong one for this engine. I would like to keep it original with a Rochester product. Any experts on carb setups for this engine? Its a stock 1967 283ci with headers, turbo350. Help!

[Alex V.]

It may not be the most refined piece, but I've had very consistent, reliable service from the 4G on my Suburban. Just a plain old square bore, 486 CFM, jet carburetor with manual choke. 486 CFM should be plenty for a stock 283. There are several options for aftermarket spread-bore carbs. that are probably less finicky than the Q-jet, but I can't speak to the traits of any. A good Q-jet really is a good piece, but they're so hard to get there sometimes...

[chefk85]

Thanks Alex. That may be an option worth looking into. Where might one pick up a 4G? I was trying to stay away from a new intake but ill do whatever it takes to get it going.

[El Dorado Jim]

Originally Posted by Alex V.

It may not be the most refined piece, but I've had very consistent, reliable service from the 4G on my Suburban. Just a plain old square bore, 486 CFM, jet carburetor with manual choke. 486 CFM should be plenty for a stock 283. There are several options for aftermarket spread-bore carbs. that are probably less finicky than the Q-jet, but I can't speak to the traits of any. A good Q-jet really is a good piece, but they're so hard to get there sometimes...

I think you have way to much carburetor for your 283, I think a smaller square bore like mentioned here would work great, that is what I have on my 70 jeep with a 283 in it...that 77 spreadbore quadrajet you have is a 700 or 750 cfm carb....you will need to find a 4 barrel manifold from the 60's....

[hugger6933]

I know this isn't the way you want to go but an after market intake and then something like either a 390 Holley or a 500 Edelbrock might be the ticket. Now if you wanting to stay with what you have [intake wise] talk to Ruggles [cliff] he IS the Quadrajet man from all I've heard and read. He literally wrote the book[several of them] on how to make them run right.

[67 chevelle]

Originally Posted by Alex V.

It may not be the most refined piece, but I've had very consistent, reliable service from the 4G on my Suburban. Just a plain old square bore, 486 CFM, jet carburetor with manual choke. 486 CFM should be plenty for a stock 283. There are several options for aftermarket spread-bore carbs. that are probably less finicky than the Q-jet, but I can't speak to the traits of any. A good Q-jet really is a good piece, but they're so hard to get there sometimes...

Amen ,, 4 jet is a perfect carb for a stock to medium build 283 , close to 500 cfm , most quadra jets are 750 , and some Pontiac , olds , are 850

[Alex V.]

I have Ruggles' book - haven't read it yet but I intend it to be my study aid when I go through my '85's carb.

If it was me I'd probably buy a good core (Ebay, etc.) and rebuild it myself. They aren't nearly as complex as a Q-jet. IIRC they came in 3 CFMs, dictated by the size of the primary and secondary bores. I'd hate to have to swap intakes, too, but my humble opinion is the squarebore Rochester is very well suited to these small, tame truck engines.

Then again, I don't know of any inherent reason your 283 shouldn't breathe fine through a Quadrajet, and before you swap intake and carb. you might be much better off just to buy a quality reman Q-jet. I'd read up before taking that leap - googling "Quadrajet substitute" should yield ample reading material on carbs that will fit your intake but aren't as touchy.

[Dimebagdavesc30]

I have a 1962 283 and I am running the qjet from the 1972 350 that was in my C30. I had to rebuild it but it seems to be working fine.... was my first carb rebuild. My first engine swap too...

[chefk85]

Good ideal all around. 4gc may be the answer but at the same time these 283 did come with an option for a qjet, dual jet, dual qjets, and an early fuel injection system. The intake is original to the truck. Dual plane spread bore pattern. I let another mechanic work on it yesterday and it is really running bad now. Backfiring through the carb and wanting to die when gassed from a stop. He tuned it by ear. I'm on my way to pick up a vacuum guage right now. Going to try another go at it myself. Has anyone sent there carb off to be refurbished? Also what is the correct rod and jet size for these engines. I've done some research but can't nail it down. Thanks for all your help guys. Good job on your first carb rebuild and engine swap!

[Alex V.]

Since the vast majority of Q-jets were installed once there was some concern for emissions, I'd try to find rod/jet specs for '66, '67, and '68 models - even if they aren't truck applications, a low-horse passenger car variant of a 283/327 should be close enough to start. I'm in the (slow) process of dialing in the jets on my 4G, on a smog-era 350 w/624 heads - I can only guess how the mixture needs will differ from the '67 327 the carb. came on, so initially I'm honestly guessing within about a .010" jet size range. Started with 61/68, then the plugs were pretty black so I moved back to 54/61 and it still runs alright but may have lost a smidgen of power and smoothness so I think my next adjustment needs to be back up. Carb. and ignition tuning on modified or hybrid-factory combos is tedious but I'm enjoying the learning curve.

[oldchevynut]

A few years ago I had Cliff rebuild and tune a Q-jet for my 1967 Malibu 283 engine. It has worked nearly flawlessly for over 40,000 miles now. The downside is at that time he had a 1 year waiting list. I think I may still have the records for the rod and jet size he used. May take me a while to find them tho...

[chefk85]

Rod and jet size would be a good start. I'd love to have a cliff built carb but I'm too impatient thanks

[oldchevynut]

Well, I've searched everywhere for those rod and jet sizes and have not been able to find them. If I do i will post them. Thats gonna bug me now...

[chefk85]

Well thanks for looking. I think ive decided to try and get this thing driveable again and just start building the 350 I have sitting around. It was always the plan anyways. However, not having this thing tuned properly will certainly bug me. I have searched far and wide for 283 original rod/jet sizes and for some reason its difficult to find info on these particular engines.

[68Gold/white]

Originally Posted by oldchevynut

A few years ago I had Cliff rebuild and tune a Q-jet for my 1967 Malibu 283 engine. It has worked nearly flawlessly for over 40,000 miles now. The downside is at that time he had a 1 year waiting list. I think I may still have the records for the rod and jet size he used. May take me a while to find them tho...

Quadrajets can be difficult to make work on smaller engines. I've been there, done that, on a 283. BUT Cliff is the answer man on that deal, as you've experienced.

There's more than just the proper rods and jets to make a Q-jet work properly on a 283.

Cliff doesn't have time to answer the phone all day. Best to email him www.cliffshighperformance.com A Q-jet would be the best carb as far as tune-ability and parts availability. Send Cliff your carb number and tell him details of your engine/car build, He can send you the exact parts you will need, and get a copy of his book.
I'd get a stock cast iron non EGR intake, it will work great on your 283.

[chefk85]

Good idea talking to Cliff. ill send him an email. I do have the original intake on the engine. Dual plane cast iron non egr. I would be more inclined to keep the 283 if I could make it run right It only has 50,000 miles on the rebuild. GM HEI and long tubes are the only mods I know of. PO didn't say if they cammed it. Sounds good through dual flowmaster 40s but not a lot of lope so I'm thinking not.

[oldchevynut]

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.

[chefk85]

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.

[Alex V.]

Originally Posted by oldchevynut

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.

That sounds right. IIRC the first cars to come with Quadrajets were '66 275HP 327 passenger cars, continuing through '67 with the addition of the 350SS Camaro. 750 CFM may be a lot for a 283 but I seriously doubt it's legitimately too much.

[68Gold/white]

Originally Posted by oldchevynut

A few years ago I had Cliff rebuild and tune a Q-jet for my 1967 Malibu 283 engine. It has worked nearly flawlessly for over 40,000 miles now. The downside is at that time he had a 1 year waiting list. I think I may still have the records for the rod and jet size he used. May take me a while to find them tho...

If you could...measure how far open the secondary air flap opens on your 283 Q-Jet. just curious how Cliff set yours up. Just push down gently on the back of the flap, measure from top of flap to front and/or rear of body casting.
Thanks!

[oldchevynut]

Will do. May take me a day or two to get to it. Randy.

[oldchevynut]

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.

[fwayne]

I have had great luck with the Summit line of carbs. they blend what is great about holley ( power valves, accelerator pumps, dual line feed and Edlebrock, simple choke, top loaded design no leaky bowls. Mine ran out of the box and only needed idle speed and idle jet tune. get the smallest size for you engine. But dont worry, even a 600 isnt too large. carbs mix the air by the used volume. they never made a Q-jet smaller than 750 cfm, so I think you'll find any smaller holley, summit or edelbrock will work.

Now to the sticky part...nothing wrong with a properly set Q-jet. They worked for 40 years on every SBC ever made till fuel injection. You might have a bad one, but its not the Qjet designs fault. I'm going back to a Q-jet myself.

[AnotherWs6]

You may want to stay original, but I will say that I just ordered an Edelbrock for my truck. It will be the third one I have installed - I bought it because of how great they ran on two other vehicles. Getting rid of a double pumper for it.

[AnotherWs6]

350 is a better motor for making power, but lacks the "cool factor" that a 283 or 327 has.