Need some advice on what carby CFM to run on my 283 SBC in my hot rod. Currently changing the cam and lifters due to a failure in components and have been wondering if my carb is enough or too much. Specs of the engine are below: - 1964 283 SBC - 0.060” oversized pistons - Performance cam and lifters (232/232 @50, 480” lift, 108 lobe separation) - Edelbrock Performer 4BBL intake manifold It currently has a Holley 570, but it’s been giving me grief prior to the cam and lifter issue. It was a Facebook Marketplace gamble in the first place, so looking to purchase something new/reco’d. Picture for attention
Those of us who live in the US don't have any idea of what's available down there. A 500-600 CFM Holley or Edelbrock 4bbl is probably what you will end up with. Don't try to get fancy, just get a basic carb. What have you found available down there so far? Or are you planning to order one from the US?
Since you had a 570 Holley on it, I'm guessing you're not concerned with a period-looking carb. If that's the case, I highly recommend the Edelbrock AVS2. The 500cfm unit will probably suit your needs, unless you plan on some higher rpm rips, then I'd suggest the 650.
That's a good lookin' coupe! Small 4bbl of your choice as suggested. Personally I like the idea of a 650......one & done.. Actually those 283's ran pretty dog-on good with the 2bbl's several million of 'em were factory equipped with!
If you're not a "Holley Carb Guy" . . . you'll love the Edelbrock AVS2 carbs. Given the price of petrol in your world, I'd probably go with the 500 cfm version on a street performance 283 that doesn't have big heads and all that jazz. Now, if you love to work on carbs, know how to really tune them, etc . . . then a 600 CFM Holley will give you a lot fo work with. In either case, it is a great idea to take the car to an experienced dyno tuner (who knows whatever carb you choose) and spend some time getting the jetting, enrichment circuits, etc - exactly right. With Holley carbs, I put my engines on an engine dyno with 'fuel turbines' to measure how much fuel is going through the primaries/secondaries and tune the carbs at WOT to use the same fuel amounts on both sides of the carb. This is a bit excessive for most folks, but it helps the front/back of the engine see the same amounts of fuel.
Nice H-R If you want a new Carb you can go that route. Just curious what your issue and grief with Carb now ? Now especially with a cam your spec's Timing will differ from stock spec's Of 7-10 deg's of initial timing & plugs heat range & ect
Over carbing can make your car run like ****. When we were dumb, know it all kids in the early 60's one of my friends parents gave him a '55 Chevy with a 265 Chevy with a two barrel and it ran fine. Hey, if it runs so well, why not get a dual four barrel set up and the car should scream. Needless to say the car ran like ****, so he compromised and went to a four barrel and it really didn't run any better than with the two barrel. Edelbrock has both 500 and 600 CFM carbs so I would give them a call with all your info and see what they recommend.
Yes, I was a dumb HS kid in the late '60's. The local speed shop's (predecessor to the SuperShop group) go to carb for a SBC was a Holley 3310. Sold them by the boat load.
@32_COOP A Quadrajet from a 308 Holden It's an Aussie thing [everything is shortened with an "E" or "O" sound on the end] Carburetor = Carby Distributor = Dizzy Transmission = ****** Ambulance = Ambo Bottle Store = Bottle O Service Station = Servo
I have two cars with '57 283 engines. One has a WCFB which is about 400cfm and the other has a 500 CFM Edelbrock. With minor tuning they both run great and get decent mileage. The Edelbrock is very easy to tune and swaping jets is a simple procedure.
Really nice looking ride! I have no clue as to what is available in the Brisbane area, and this may have some effect on what you purchase. As far as required CFM is concerned: In 1957, when Chevrolet built a race-only version of the 283, Mr. Duntov chose to use a Carter WCFB number 2493s which was rated at 380 CFM. Four barrel carbs from 295 CFM to 675 CFM were available on various production street V-8's in 1957, but 380 CFM is what was chosen. Small primaries will give better low end response. So depending on what might be available, AND what your intake manifold will accept with NO adapter: a 400~450 CFM square-bore (primaries flowing about 200 CFM) or a 750 FM spread-bore (smallest older Rochester Q-Jet, at least here in the USA, primaries flowing 150 CFM and an "on-demand" secondary). Of course, with a properly sized carburetor, you will automatically lose all of the "bench" races ! Jon
Hey mate!! The issue I am having with the 570 is I plant the foot, get heaps of noise and movement, pull off the gas completely and it dies. I chalked it up to either flooding or starving. I’ve also had issues with the bowls prior to this with cracks etc. Getting to the point where the Facebook Gamble Carby is not worth playing with right now.
@32_COOP Just asking , Do you know of some little tricks , Like transfer slots , & squirter, Spring adjustment for if Vac secondary . Float leave , bigger needle & seat , Timing curve . With a cam most of time you need to adjust the blades up/ more to get to idle Then blades are out of transfer slot on front barrels , cause a bog. So you can take back barrels & adjust more of ****erfly gap So you can lower Front ****erfly to get back into transfer slot's so from ideal , squirter shot works correct to solve bog / lean . squirter adjustment leaner or richer . If back barrels Va*** there a set screw to adjust rear ****erfly's , screw is in base-plate up side down . Double pumper has adjustment like front ****erfly's.. Another trick you can drill like a 1/8 inch Hole in front or rear Or SomeTimes Both ( all 4 ****erfly's ) Just a thought if you are not aware of You will need @ least 14 deg's plus of BTDC timing @ Idle & me I like 850 -950 rpms idle Some times 1,000 - 1,1000 Both stick & auto with loose converter.
Thanks mate!! I’m currently installing that cam and lifter setup now that I previously mentioned. I will take all your advice on carb adjustment on board when I throw it back for the break in. It runs a treat for a break in, just doesn’t like being let go from WOT to idle. I’m sure I’ll find the issue one of these days and if not, time for a treat (new carby).
Have you checked your float levels? Set them about 1/3 of the way up the sight gl*** if you have those, or so fuel just trickles out of the hole if you have plugs.
Float levels are set perfectly, still conks out after getting off WOT. I lowered the float level and it got better, but then it starved for fuel on idle. Just put it back to normal and drive less like a silly ****** is my fix at the moment. Definitely want to be able to mash it though as I have some dirt drags coming up soon.
Some things to try...... Accelerator Pump: Rapidly snapping the throttle shut or open disrupts the fuel-to-air balance. The accelerator pump provides a quick squirt of fuel to compensate for this vacuum drop. If the pump is worn, torn, or clogged, the engine will experience a sudden lean stall. Idle Mixture Settings: If the idle mixture screws are set too lean, the engine won’t catch when the throttle valve closes and the airflow transitions from the main jet back to the idle circuit. Float Level: If the float is set too low, the carburetor bowl can temporarily run out of fuel during high-RPM WOT operation, leading to a stall. You have already crossed Float Level off the list.
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