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Best Carburetor for 350 small block?

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Old 11-27-2010, 09:55 PM   #1
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What is the best carburetor to slap onto a Chevy 350 small block? Only current mods to the engine are a racing cam, doug thorley headers, an Edelbrock intake manifold with venturi pattern to fit a Rochester but not like stock. Image will be available. If I get an Edelbrock carburetor with the 4 venturis the same size, then will I need an adapter plate? My Rochester was damaged due to a friend's stupidity with it. I need something cheap too. Are there any suggestions?

First Image shows venturi pattern in intake manifold. If a better image needs uploaded, I'll do that. Second Image is the engine put back together with faulty Rochester put on it. Does not run right at all, needs new carburetor. Need some possible pointers.
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Old 11-29-2010, 07:33 AM   #2
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Hi The1965Ghost


How about trying to locate another Rochester carb from your local scrap yard or ebay ?


http://motors.shop.ebay.ca/Carbureto..._nkw=rochester

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Old 11-29-2010, 02:51 PM   #3
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The scrap yards here usually don't have anything good. I've looked on ebay. I'm just not so sure and trusting in the conditions of the used carbs.
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Old 11-29-2010, 03:03 PM   #4
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Check with a place like Jeg's:

http://www.jegs.com/c/Fuel-Carbs-Int...10271/10002/-1

Get out the plastic, not cheap.

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Old 12-17-2010, 12:26 PM   #5
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What about a 750CFM Edelbrock at Autozone along with an adapter plate?
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Old 12-17-2010, 12:38 PM   #6
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750 sounds about right......primaries are the same size as secondaries?? Been a long time since I did any carb mods....... The manifold you have should accept the Edelbrock with no adapter.....it is an Edelbrock. I once put a 715 dual inlet Holley on a 283 small block........no major mods to the engine but it would take all the gas the Holley could throw at it. Wasn't too long ago......brand new Holley from Jegs was $45......
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Old 12-17-2010, 02:11 PM   #7
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IF it had a QuadraJet on it it'll be a spread bore manifold and will need the adapter, unless you get the spread-bore replacement carb, for 5000 RPM and under 650 CFM is plenty.
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Old 12-19-2010, 08:02 AM   #8
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Wrench is correct on both points.
If the carb is too big, partial throttle response is effected and reduced. Air must pass through the carb at a certain spped in order for the venturi effect to happen correcly. With a carb that is too big, the vacumn drop is insufficient to draw the fuel and to atomize it correctly.
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Old 12-19-2010, 10:06 AM   #9
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i seem to remember they used holly double pumpers on them a few years ago
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Old 12-19-2010, 11:47 AM   #10
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Yes`they did but at lower RPM's the torque curve flattened out from running too lean(not enough air flow to draw fuel through the venturi, the larger CFM allows higher RPM but for street use the 650 has better drive-ability and a better low end torque curve.
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Old 12-19-2010, 06:46 PM   #11
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What rpm/powerband is the cam for? It is hard to under carberate easy to over carb your engine.600 cfm is a good start.
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Old 12-20-2010, 04:16 PM   #12
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The Edelbrock 750 does has primaries same as secondaries. If this manifold can take a Quadrajet then I'd need that adapter I thought. rpm/powerband for that cam I never checked that out. I wasn't the one to install the cam. This 750 is cheapest. If it has a good possibility of being too much CFM then I'll keep lookin.
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Old 12-20-2010, 04:31 PM   #13
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750 will work but, the drive ability around town would be better with a spread bore(small primaries, large secondaries) and by the time you add the adapter and make sure you have hood clearance after raising I would look for the Qjet replacement.
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Old 12-20-2010, 04:44 PM   #14
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Oh yea in this truck theres enough clearance. Quadrajets are expensive though. I guess I'll just look for them. Does Edelbrock still make their Quadrajet style carburetor? What other brands make them too? Just Rochester and Edelbrock?
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Old 12-20-2010, 05:33 PM   #15
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Holley still makes one > http://www.jegs.com/i/Holley/510/0-8...0002/-1?CT=999
Edelbrock stopped a couple years back but they are still around the only problem is the electric choke models were all 795cfm and above, the smallest was 750 but used the divorced choke setup where the bimetal spring was mounted to the crossover runner on the manifold.

Look around at your local speed shop for used ones sometimes you can get a really good deal.
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Old 12-20-2010, 05:39 PM   #16
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Just a thought... Could your issue be resolved by rebuilding the carb, or was the damage done by dropping the carb?
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Old 12-20-2010, 06:31 PM   #17
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That is a good point.
A rebuild of the original, with some bigger jets to work with the cam, may be a good idea.

Here is a Holly for a cheap price, but will need a rebuild.
http://cgi.ebay.com/ebaymotors/Holle...item45f577b841
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Old 12-20-2010, 08:10 PM   #18
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Quote:
Originally Posted by pat mcgroin View Post
That is a good point.
A rebuild of the original, with some bigger jets to work with the cam, may be a good idea.
lol and the cheaper route than going out and buying a new carb... most rebuild kits are less than $70. Very easy to do, just takes a little longer to get the carb set up after a rebuild. Local parts shops usually carry them in stock.
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Old 12-21-2010, 12:33 AM   #19
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Cool Holley wrench97.
My Rochester was dropped in DIRT and the choke was broken off. Secondary flaps (top flaps) do not open with throttling. I have some videos on youtube of the thing running before and one after the carburetor was screwed up. Engine sounds like a pile of junk with it now.
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Old 12-21-2010, 07:07 AM   #20
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The Holley I put on my 283 did not have a choke...... No problems with starting in the winter....pump the pedal about 8-10 times (before hitting the key) and it fired right up. Driving was another matter....had to baby the pedal for about a mile. Try to give it too much gas and it bogged down....

Secondaries were pinned and I knew just where they kicked in. First time riders thought it was pretty quick.....I let em get used to the acceleration for a few short romps going through the gears (4 spd)....then when they least expected it I set em back in their seat.....

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