CFM'S on Motorcraft 2350

[Mud Thrasher]

Ok I was talking to a mechanic friend yesterday about leaning out my new edelbrock 1405 and we got into a discussion on it. I'm running rich right now and he was saying that 600 cfm's was too much for the heads and (setup) and such on my motor. He was saying that I would never get it leaned out right. He was saying that my motor was set up for a 2 bbl and not a 4bbl. Were the the motors for the 2 and 4bbl set up differently on our rigs? Just wanting to know so that I can say I told you so( even though I don't have half the mechanical knowledge he does).
On a different note I am pleased to say after the body changeout that I didn't know that our rigs were supposed to be that quiet. :D Also it runs soooo much better now. I guess that my prob was wiring. Holes = rust and shorts. :eek:

[joe]

I don't know the CFM rating is of a 2350 but your wrench is blowing smoke. Myself and prolly hundreds of others are running the 1405/1406 Edelbrocks on our 360/401's and are liking it. They work just fine.

[joe]

As an addendum, yeah they do run rich right out of the box but use a vacuum gauge or handheld tach to dial in the mix screws and you'll be fine. If you offroad it you'll want to get the offroad kit for it and lower the float level a far as possible to reduce flooding in off-camber situations. If you are going to "seriously offroad" it I would go back to the 2350 then. Just about any 2v carb is better offroad than any 4v carb regarding the flooding/off camber thing. The Edelbroc isn't as good offroad as a Qjet but neither are as good offroad as the 2v 2350. Just my $0.02

[nograin]

Well, maybe he know how things go together, but he clearly doesn't understand the fundementals of how things work.

The number of barrels has little to do with running rich or lean. The fuel just sits in the bowls. It is drawn into the air stream by the air rushing past little passages with restrictions, on the main circuit they are called jets. On the idle circuit they are needle valves you adjust. Thats what controls rich and lean.

A four barrel is like having 2 , 2-barrels with the 2nd carburator coming into play once the first one's throttles are between half and 3/4 open. This can be actuated mechanically by the linkage or by a vacuum signal, but the idea is the same. You basically only run on 2 barrels from idle through cruise.

There are two advantages here. One, you can make the primary barrels smaller because two more are on standby. Smaller barrels can provide better vacuum signal at low rpm, and thermodynamically a throttle is most efficient when it is open more. In other words a big hole partially open is not as efficient as a small hole mostly open. The other advantage comes from the first. Since the primary barrels got you covered for low rpm, the secondaries can be made so the total airflow possible is higher and not mess up the bottom end.

Take your 360 for example. It uses 360 cubic inches of air every 2 revolutions. To go 6000 rpm, the volume of air fuel mixture needs to be at least 360/2*6000 very roughly.
(Thats in cubic inches. Carbs are often rated in cfm measured with a 2"Hg pressure drop).

The point is that 4 barrels, and carb ratings in general, are about VOLUME, not about mixture ratios.

[Stuka]

And just a little FYI, 360's all had the same heads. No differance in 2v to 4v heads as far as I know. (unlike GM's and fords) And does he know that 360's have HUGE ports for their size? Bigger intake valves then a chevy fuelly head.

And at 5000rpm a AMC 360 requires 519CFM at 100% VE. The needed CFM will go down if the VE drops. Which it does. But...you should always have about 100-150cfm more then what you need if you want max power.

Go here --->http://www.edelbrock.com/automotive/math.html

That will tell you how much CFM a certain motor should have. As well as lots of other cool information reguarding engines.

[JOECOOL]

I run a 850 Thermo Quad on my 318 mopar. Too much carb, NOT.
The Edelbrock ues small primaries almost the same size as a Q jet. You are talking maybe only 250 cfm. The rest is out the secondaries. You just need to rejet it since that carb is metered to work on any motor it is jetted on the rich side for engine safty reasons. Its then up to you to get it adjusted.
My holley needed to go down 4 jet sizes to get it ok.