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03-19-2006, 10:48 PM
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#1 |
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Registered User
Join Date: Apr 2003
Location: Central PA....In the Berg of Nisbet
Posts: 790
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Carb Size for 454?
I have been fiddling with the 454 in my K-20.............It runs better, but falls on it face on a hill and still seems sluggish when you stand on it. The previous owner put a new Edelbrock on it, and I haven't checked yet, but I am wondering if he didn't go big enough for this size cube engine. What should I be running on it? Everything else is spot on, and it runs well, other than the problem I mentioned above, it just doesn't seem like its getting the fuel/air on a pull. I put all new filters/plugs/wires on it so it isn't any of that that is the problem, and it has an electric fuel pump that works really well.
Still haven't checked the block #'s, but I am wondering if this isn't a smog engine and it will be a turd?
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'72 K-20 EFI'ed 250 Inline/4spd stake body, Farm Truck '71 C-20 Cummins Diesel Powered, In storage thanks to $5.00 diesel! '69 3500 GMC 305V-6/4spd, Still under reconstruction.......... Inlines Rule! 6 soldiers standing is better than 8 laying down!!!!!!!! |
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03-19-2006, 10:52 PM
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#2 |
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Account Suspended
Join Date: Mar 2003
Location: ** THE FALL GUY **CHICAGO IL
Posts: 5,883
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Re: Carb Size for 454?
750 cfm to 800 cfm to 850 cfm depends on the cam size
750 for sure |
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03-19-2006, 10:56 PM
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#3 |
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Registered User
Join Date: Nov 2003
Location: st. louis area
Posts: 1,551
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Re: Carb Size for 454?
if its a stock or near stock 454 Id use either a Q-jet or a 750 cfm carb.
Ive got a 770 Holley on my mild 454. John
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75 GMC C-15 short/step factory 454, lowered |
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03-19-2006, 11:00 PM
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#4 | |
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Registered User
Join Date: Apr 2003
Location: Central PA....In the Berg of Nisbet
Posts: 790
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Re: Carb Size for 454?
Quote:
__________________
'72 K-20 EFI'ed 250 Inline/4spd stake body, Farm Truck '71 C-20 Cummins Diesel Powered, In storage thanks to $5.00 diesel! '69 3500 GMC 305V-6/4spd, Still under reconstruction.......... Inlines Rule! 6 soldiers standing is better than 8 laying down!!!!!!!! |
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03-20-2006, 11:00 AM
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#5 |
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Post Whore
 
Join Date: Feb 2000
Location: Rose Hill, KS, USA
Posts: 12,684
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Re: Carb Size for 454?
I'm using a Jet Stage II 800 cfm quadrajet and my 454 seems to like it alot.
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1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14 |
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03-20-2006, 11:47 AM
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#6 | |
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Dork For Days
Join Date: Aug 2005
Location: Dallas
Posts: 407
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Re: Carb Size for 454?
Quote:
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1972 C20, 402/700R4 - My first classic truck, bought in September 2005. 85% transformed from "Farm" to "Cool" status!  1970 Dodge Challenger 440, 4sp (my other toy) 12.67 @ 117 MPH, with a pathetic 2.022 60' 2007 Dodge Charger SRT-8 2008 Cadillac CTS All-American garage, baby! |
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03-20-2006, 02:31 PM
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#7 | |
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Account Suspended
Join Date: Sep 2005
Location: Monroe, WA
Posts: 3,815
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Re: Carb Size for 454?
Quote:
 A Q-jet flows about 780 CFM, and even some fairly warm Corvette 454s shipped with them. I'd stick with a vacc secondary carb.There are a lot of things to look at with the symptoms you're noting, but I'd be surprised if it's the fuel pump. My guess is a) timing advance or b) the point where the secondaries are kicking in or the metering rods. I'd keep the Edelbrock and tune it vs. making a change. They're great carbs for engines making <= 1.2 HP/CID FWHP. |
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