can carb be too big?

[firechero]

the previous owner put a 750 edlebrock carb on my 360, what kind of problems can that cause, i know all i need is a 600 series

[89grand]

Over carburation will cause stumbling problems when you mash the pedal.

[ August 21, 2003, 04:38 PM: Message edited by: 89grand ]

[Heavyjp]

You mean like I have with my friends Edelbrock 850 electric choke! I'm still using my stock intake too. Yes, stumbling is the norm. I just don't try to floor it, but if I do she won't cut off she just does the gasplike hesitation and I just get off it and drive normal. She does pickup better at highway speeds. I just don't have the duckies to fund my 4-wheelin project right now. I am working on my wifes car Buick/Le Sabre-v6 front drive. I'm changing the Crankshaft sensor. It's takin me the better part of the week just to get that dam Harmonic Balancer/Crank Pulley combo off. Front wheel drives suck. Oh yeah the 4 barrel intake is on my list after hers is done.

[firechero]

well i have the edelbrock performer package on my 360 but im thinking that a 600 would stop some of the stumbling problems i have, does it matter that i have an electric fuel pump? do u know if i can return my 750 for the core charge for a new 600 ?

[AMX factor]

Electric pump can't hurt unless it's output psi is too high. There shouldn't be a core charge on the new 600. You just buy them outright. Summit Racing or Jeg's would be a good place to buy new. But if your interested I have a 625 Carter AFB which is same as Edelbrock that needs a rebuild that I'd trade with some cash for your 750 Edel.

[firechero]

id like to get a new one, just like my 750, cept smaller, the linkage works perfect with my cruise control

[Spudz]

"tune" it with some JB weld molded into the venturis. If you had a flow bench it might just work! smile.gif

[firechero]

i just bought a performer 600 from jegs, so ill have a nice 750 for sale here soon!

[will e]

Hey everyone SPUDZ is just kiddin'

Problem with bigger carbs is velocity at lower RPM and the ability for the carb to react quickly when you goose the trottle.

The velocity helps fill the cylinder with air.

Most folks 'over carb'. A big carb is only really helpful if you are running higher RPMS.

[davez26]

This is why I like the Quadrajet. Tiny 200 CFM primaries for low speed operation, and big vacuum secondaries that only open as much CFM as needed. To bad they are such a drag to mate to an AMC motor.

[J4GRAND]

I have a 750 CFM Edelbrock 1407 on my rebuilt 360 and love it!! With the Summit K8600 cam and aluminum intake, I have no hesitation when I mash the pedal. One of the big things I did (highly recommended by my machinist) was to use a 1 1/2 spacer between the intake and carb. The bigger the carb cfm, the better airflow you want- the spacer really helps in that regards. The airflow issue has gotten even better since installing headers- LET THAT ENGINE BREATHE!!!

[Mavawreck]

ive heard with over carburation you have to be careful cuz its possible for unburned fule to wash the oil out of the cylinders and cause premature engine wear. Im putting a 600cfm edlebrock on top of my performer intake, would yall recomend putting a spacer in there and am I going to have clearance issues with the hood? All my insulation is gone. Will i need to change from the stock air cleaner too. Sorry, didnt mean to jack the thread but yall were sorta on the topic.

[Bob Barry]

Ironically, too-big of a carb results in not enough fuel, as the poor velocity in the venturi doesn't draw out the necessary amount of fuel. Hence the off-idle stumble, which can be compensated for by increasing the accelerator-pump shot, richening the idle mixture or richening the main jets. It's a bandaid, just to cover the flaws of a larger carb, but it can work.

[firechero]

i bought the performer 600, maybe it will keep my plugs from fouling so much, i think i was running rich no matter how i tuned the 750

[will e]

Originally posted by BobthaBuilder:
ivIm putting a 600cfm edlebrock on top of my performer intake, would yall recomend putting a spacer in there .I would start off without it. Then try putting it on. See which one is better. Different engines/setups will react differently to these types of mods. The only way to know is to try.

If you are happy with the performace without the spacer (and don't want to mess with trying one) then don't. If you are having issues with the carb then we can look at the problem and decide if a spacer might help.

Sounds like a good setup to me.