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#1 |
Registered User
Join Date: Oct 2002
Posts: 90
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Is my Carb too big?
I have a stock crate 350 from GM that I put in my truck. It's an '85 gmc 1/2 ton 4x4. It has 33" tires, a 4" lift, 700R4 Tranny, and 3.08 gears, which were stock. The stock carb on it was trash. I got an Edelbrock model 1904, which is 795cfm. I thought that was way too big, but a couple of peple have told me that it isn't. My truck has little umpfh behind it when I'm driving down the highway or going up hills. I have to keep my foot in the throttle so much that it's ridiculous. Also, towing is horrible, as the truck seems to have no muscle. I know that with tall tires like that and 3.08 gears that I'm really down in the 2.xx range, but could my carb have something to do with that too. How about my horrible gas mileage, like only 100 or 110 miles per tank
(16 gallon) on the highway. Would I be better suited with a 650cfm carb? I also thought about putting a cam in the truck to try and help out, but I don't want to void the 3 year/36,000 mile warranty I have on the crate motor. Any advice? I'm a carb newbie...so, all is welcome. J |
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#2 |
Registered User
Join Date: Mar 2003
Location: Columbus Ohio
Posts: 1,413
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The only real problem with a big carb is throttle response (and to a lesser extent gas mileage, although not much if it is tuned right). That carb is a little too big for your application. You would be better off with a 600-650 carb.
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#3 |
You get what you pay for
![]() Join Date: Dec 1999
Location: Cherryville, NC
Posts: 4,798
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I disagree.
The 1904 is designed for 305's through 454's. It's a vacuum operated secondary carb, so your engine only takes what it needs, just like any ole Q-jet always has. I have a 1904 on my truck and it works great. Remember, it's a Q-jet. It's the same as any Q-jet ever was. Q-jets came on 4.3 V6's you know?
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Mike 1985 Chevy C-10 |
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#4 |
Registered User
Join Date: Oct 2002
Location: Phoenix, Arizona
Posts: 4,703
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I also have a 1904 qjet on my stock 350 w/ no problems.
Edelbrock does list the 1904 as a direct replacement that meets emissions requirements.
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#5 |
Registered User
Join Date: Mar 2003
Location: Columbus Ohio
Posts: 1,413
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honestly......I was under the assumption that the 1904 was some type of AFB style carb as most other edelbrocks. Sorry.
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#6 |
Senior Member
Join Date: Mar 2003
Posts: 2,500
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Get a Holley 650.....this is better suited to a 350 than that "universal" carb you now have.
It will support 6000rpm. |
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#7 | |
Registered User
Join Date: Jul 2001
Location: Atlanta GA
Posts: 1,704
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Re: Is my Carb too big?
Quote:
I bought a stock crate and the harmonic ballanced and timming mark were mismatched. The ballancer needed the timing mark that you veiw between the water pump nad the block and the timing tabe was to the driverside of the water pump. That's about 20 Degrees retarted. It will run like that but like crap. Mess with your timing and I bet you find the problem. Your truck may also have ESC spark control and from what I have read the knock sensor for a 305 is different then a 350 so that could cause you problems.
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Grim-Reaper 70 Pontiac LeMans Sport Convertible, worlds longest resto in progress Looking for 71-72 2wd Blazer or Jimmy Project |
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#8 |
Hotwheels?
Join Date: Dec 2002
Location: Pleasant Hill, CA
Posts: 1,145
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Before you start messing with your carb. Id get some 3.73's for those tires. They are bottlenecking your power tons.
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1978 Money Pit - CUSTOM DELUXE!!!! |
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