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  #16 (permalink)  
Old 12-31-2011, 01:21 PM
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Holley all the way here not a big fan of the Proform products, But not saying they don't good some good stuff on the market i am sure they do. JMO


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Old 01-04-2012, 07:35 AM
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Intake manifolds

For a basically stock engine in a Street Rod that is DRIVEN to rod runs, I go with square bore, dual plane. If AFB carb, always use a 1" phenolic spacer to eliminate percolation. If new Edelbrock, go with regulator set at 6 psi or 6.5 psi max pump....Chevy OEM pump is about 12 psi. Edelbrock thinned the brass floats 2 years ago.....it will dribble.
Otherwise, big on EFI........
Jim, School of Hot Rod Hard Knocks, 1957
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  #18 (permalink)  
Old 01-04-2012, 07:44 AM
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If you want a good simple carb that is easy to tune and gets decent mpg's then go with an edelbrock.
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Old 01-04-2012, 08:11 AM
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Used them all

Hey... got all that information now? More confused than when you started? I had the same question about ten years ago, and eventually went with a holley... why? Because I could afford it.... The Edelbrock performer is the easiest to install and I found that Holley has techs that will help you with anything... free... and are very knowledgeable.... The bottom line is that you go with what your intake will dictate and then I would suggest you buy something that you can afford, that works for you, and has tech support if you do not know much about carbs and rebuilding yourself. A local established parts store may be just a little more expensive, but they have to live with you too.... My Holley problem was the gas boiling in the bowl and Holley went out of their way to show me the plate I needed to divert the heat from the intake.... There... I think I added to your confusion.... final thought... no matter what you go with, it will probably be just fine for what you want...... carbs have been around forever... and for the most part, all of them are decent.....
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Old 01-05-2012, 12:34 AM
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Ive had every design of carb on my truck and the Rochester carb was the best running one I have ever had. Initially it has all of the problems that a lot of people complain about when tuning Rochesters. After I learned how to tune it, which was really easy to do once you have done your homework, you will love that carb. Edelbrocks are slightly modified Rochester designs, because Roshesters are a little more efficient design than holleys. That's why Edelbrock has so few part numbers to cover most all applications, unlike holly. I just wish Edelbrock made a spreadbore option. Right now I have a quickfuel on the same truck, partly cause I wanted to learn how to tune them too.

Go with Edelbrock for ease of tuning, Rochester for max MPG, or a Holly style for max power, but you gotta be a pretty good tuner with the holley to realize any real difference.

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Old 01-05-2012, 04:06 AM
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Totally Agree

You summed it up very well and I totally agree with what you said. I have had them all too, and the bottom line is that anybody who tells you one is the best, he is saying that because of what he has found over the years and I respect that. I just have never ruled anything out ever. Some carbs definitely are easier to work on than others. My latest project rat rod is getting a 4.3 Chevy V6 and I searched high and low for a 1985 motor. It came with a four barrel intake stock with a carburetor. Not long after, they went with a fuel injected motor, with an expensive fuel pump system and a computer. I don't have ANY of that, good or bad. I still like to work on carbs.... and have tackled some of the toughest ones to rebuild. I figured if I screwed it up, I was no worse off than I started, unless I dropped a bolt down in it..... Have a good one....
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Old 01-05-2012, 04:46 AM
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Hey Dave,,,Arthur here,,a lot of what everyone has posted fairly answered your question,,that being,,,whats the difference between the spreadbore and squarebore.The thing that you have to keep in mind is how is the 340 that you're working with built.Is it stock,,has it been modified,so on and so on.As one of the guys posted,,the stock carb was a thermoquad,,and if tuned right,,you can't beat them.When you start getting into aftermarket fuel systems you have to take into consideration what your engine NEEDS,,that's a very important question,,,"what does it need?",,,are you cruising,,are you racing it part of the time,,,can it handle huge amounts of fuel?Everyone here is right,,,the Edelbrock Performer carb is absolutely the easiest one to tune and to work on and you can get really decent performance levels out of that carb,I run a Edelbrock 800cfm for the street and for my engine combination it performs excellantly.Holleys are tricky,,they require a lot of tuning to get them to work on the street AND the strip,,,and there are at least 15 different aftermarket variations to choose from.Edelbrock makes a good spreadbore,like the Q-jet as well as Jet-Performance and they make a really great Q-jet.Holley also makes a spreadbore,but again,,you get into the tuning of that carb just like a regular squarebore,,aka,,jetting,power valve,emulsion tubes,boosters,,so it makes the Holley version a lot more complicated when getting it dialed in.Just remember,,,answer the question,,,what does my engine need,,if it's a stock build,,I would stick with the spreadbore because that is the way it was originally built.However,,if you have any questions or need information on any of these variables,,give me a shout,,,and I can give you the websites and calculation charts for your engine combos.
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Old 01-05-2012, 06:35 PM
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Originally Posted by daveh
Hey guys,

What's the difference between a spread bore and square bore carb? I'm putting it on an Edelbrock LD340 on my 340 1971 Challenger. Which do I need? I'm looking at the Holley 650 double pumper. Thanks.

Period correct and a very decent carb for this would be the Edlebrock version of the Carter. It's really an AVS rather than an AFB but 40 years later I'm not sure even the trained eye now wearing bi-focals can tell the difference.

This is a nice carb it's not quite a spread bore in terms of a really big secondary and a tiny primary bore like the Q-Jet, still it puts a smaller primary and larger secondary into a square bore box. It uses metering rods on the primaries like the Q-Jet which usually are more sensitive to cruise fuel needs than Holley's. The secondaries use an air valve like the Q-Jet which makes it harder to over-carburate the engine when you get on it and revs aren't up to where the engine can use the extra flow yet.

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