Bigger Carb on my 340

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We just put a 770 holley street avenger on my friends with a build like yours and he loves it but we are partialto holley.
 
Holley all the way ...edelbrock carbs seem cheap to me and make engine look like a Chevy motor lol had a 670 avenger Holley on my old 360 that thing would get down now have a 850 dp on my stroker and love it
 
dustya_383 said:
Holley all the way ...edelbrock carbs seem cheap to me and make engine look like a Chevy motor lol had a 670 avenger Holley on my old 360 that thing would get down now have a 850 dp on my stroker and love it
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I find that comment mildly disturbing since the Edelbrock carb is a updated version of the Carter car. That came stock on MoPars since the early days. To liken The OE or up dated version of the Carter carb to a Chevy and placing it in the me to class of car stroke a nerve.
 
Paladin06 said:
I'm thinking about going to a New Edelbrock 750 CFM Performer Series Carb/Carburetor w/ Electric Choke, 4BBL from the Edelbrock 650 I have on the car now. The engine has been bored 30 over, it's got a purple cam, high rise Edelbrock Street Performer Intake, Doug's Headers and HEI ignition.

Your thoughts please.
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I doubt the extra CFM is going to make a difference In a big way. While this statement is a bit broad, your engine discription is very short on details.

The carb is part of the combo, the whole engine package.

What exact intake and cam do you have?
What is the gear ratio and tire size?
 
As Rumble says,the Edelbrock is pretty much the carb 340's were born with.
and stick with the 650 if it's the Thunder series.
 
I have a 750 eddy on my 340 and LOVE it. I have been a holley guy for years but have to admit that the eddy is a great carb. I say go for it!!
 
I tried a number of carbs on my old 340. It was pretty mild. Not sure of the cam but I would guess it was in the 225* @.050" range, LD340 intake, Headers, recurved distributor, Mopar Performance heads (LA castings) and unknown compression. It has a 600 Edelbrock on it when I bought the car which ran really good after a metering rod swap. The Holley 650 Double pumper ran good. The Edelbrock 750 never ran right even with tuning. The last carb I used was a proform 750 which ran really good too.

Id stick with the Edelbrock 600 for a street car, easy to tune, great throttle response.
 
the age old debate of which carb is better sparks many opinions...

no matter which carb you buy...you will need to make adjustments to work on your car...

so the question becomes how good are you with adjusting a carb...

do you know how to work on a eddy?...do you know how to work on a holley?

as said..pick you part and spend your money...
 
either brand carb. can work just fine. It's all in the tuning......even thought I like holleys.
 
There's a set of posts that speak the most true words.
 
Are you runnning a 1406 or a 1407 on it now?

There is no 650CFM Edelbrock Performer/ AFB.

If you have a 1406, the 340 is pulling through a 600CFM, which is likely too small for that engine with that combination.

Honestly, I think 750 is too much for it. Technically, it will only use as much as it needs, but I think 625-650 would be a good number to shoot for in that engine.

If you don't want to mess around with linkage changing, I would suggest going with one of these, which is an 1807. -

http://www.summitracing.com/parts/edl-1806/overview/

I'm convinced that these designs were all dry CFM rated, which is optimistic, compared to a wet CFM rating.

Either way, I think the AVS, which is essentially a more tunable AFB, will bring you a better run than a 750CFM AFB with that cam, over a 1406 600 CFM AFB, if that is what you are running.

Other companies like Demon and some Holley units are wet CFM rated, which brings true CFM on the advertised rating. I'm running a Street Demon 625, which is likely similar to a thunder series AVS, although I don't really know, because it's a 3BBL, so it's not quite apples to apples.
 
On that combo , I wouldn't buy a new carb just for the extra cfm. I really don't think you would notice any " seat of the pants'' horsepower you could feel. Just my 2 cents . Good Luck
 
It depends. I agree if the car actually has a 650 CFM Edelbrock on it, which would have to be a Thunder AVS, but that number is widely misunderstood. People throw around "650" on the typical 1405/1406 readily available carb and it is a 600CFM, which I don't think is quite enough for that engine.
 
I used to have flooding issues in hard turns with an old AFB I used to run. I don't know if that was inherent to that carb, or maybe my float level was too high. Anyone else have that problem? That's one thing I never had with my Holley.
 
Thanks for your input. The car does have a 1406 carb. The rear end gear is 3:55. The tire size is P245/60R14 and it is a 4 speed car. The carb has not been rejetted.

DaveBonds said:
It depends. I agree if the car actually has a 650 CFM Edelbrock on it, which would have to be a Thunder AVS, but that number is widely misunderstood. People throw around "650" on the typical 1405/1406 readily available carb and it is a 600CFM, which I don't think is quite enough for that engine.
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I have a 600 and 750 Ede. I have run both of them on my warmed over 360.
The only advantage I have found that the 750 has over the 600 is in the very top end.
I pretty much drive my cars street light to street light,so top end is never met.
All around performanceI give the edge to the 600. The car is quick,and just runs well with it. I just bought a 650 from a member,so I will be toying with it to see how it runs.
I would think a carb in the 650 range would be ideal.

With that 4spd you can take advantage of a Holley DP as well.
 
Paladin06 said:
Thanks for your input. The car does have a 1406 carb. The rear end gear is 3:55. The tire size is P245/60R14 and it is a 4 speed car. The carb has not been rejetted.
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It's not getting enough air through the entire range of RPM and it's running sea level jets and rods.

East Valley and Phoenix AZ is at about 1000ft, so you aren't terribly rich, but the combination certainly isn't doing the engine any favors, with that cam and those headers. It would eventually start fouling plugs and without tuning, you won't get the throttle response you are after.

A 650 Holley DP is a good choice on a 4 spd, for CFM, etc. It depends on what kind of vacuum you are seeing on that engine, with that cam.

I think there are better carbs that use more modern technology for the street than a DP or AFB, but everyone will have their own opinions.
 
Cudavert, the carb was ill set with those troubles.
 
Your set up sounds similiar to mine. I use a 750 holley DP and am very happy with it. I woudn't worry about a choke either, 5 pumps and mine starts every time.
 
Dave's advice is good (eg post #20)
You will do will with money on a rods, jets and springs coupled with some tuning time on a dyno, or at the drag strip or other repeatable venue.
If you haven't looked at the spark plugs, they'll give you at least a general impression of what's going on even if you're not an expert in reading them (that's a bit of an art). Start with a new set before the first dyno or 1/4 mile run. That way you get a clean read of Wide Open Throttle. Same when you do your around town or highway tuning.
 
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