Carb need cleaning?

[AAXD530]

The Edelbrock instructional videos on Youtube, which are quite good, suggested my car could be over-carbureted. I have a '69 GTX 440 with a Edelbrock 1407. A 750CFM unit. Anybody have any thoughts on that? Is that a bad match? Would a 600 be better? That is what he suggested.

 

[coloradodave]

Edelbrock's general guidelines are for a completely stock motor used for transportation. If you have modified your motor and have done so with performance in mind, the recommendation may change. What's your situation and intended use?

 

[rlsbee]

My car has a 383 with a MP 284/484 cam, and some mild porting on the 906 heads. I had a Edelbrock 750 (AFB type) and I could not get rid of the low end stumbling. Not real bad, just wasn't what I wanted it to be. I had a chance to try an Edelbrock 650 Thunder series (AVS type). It worked real nice so I bought one and I've never been sorry or regretted the smaller carb.My car is strictly street driven. It's got a Tflite with 3:23 Sure-grip. I also run a Pertronix billet distributor. Just to share my experience with 'downsizing'.

 

[Meep-Meep]

I ran a Eddy 750 on my 440 but it's not bone stock. It has a small cam and some compression to back it up and that 750 works very well on the factory intake. If you end up with the 600 it won't hurt you for street driving. Might kill some top end but over all it will run well. The factory 440 AVS was not quite 750 CFM and I'm pretty sure it was more than 600.

 

[shag766]

i am using a single 850 holley on the not stock hemi and i love it. i know it will take more but then you get into tuning issues. much more better to just jump in and drive.

 

[67 coronet]

running a bone stock configuration calls for about 637 cfm by the math.(with a 5000 rpm cap)adjusted up to next size would be 650 cfm.as stated earlyer,if you have done any mods to the motor it would want a bigger carb.either way a 750 cfm carb should work with some minor tuning.by no means is that "over carbing" that motor.

 

[AAXD530]

Thanks gentlemen. I appreciate the advice. Now how about cleaning. The last owner (I just bought it in Feb) put on about 100 miles in 12 years. That can't be good for a carb. What is the best way to clean a carb? Can you take it off and soak in anything? It must have some gunk in it for sure.

 

[AAXD530]

It has this stumble when you punch it even lightly. Idles fine. Runs down the highway great but to get to that highway speed you have to go through the stumbles. Assuming lack of use and maintenance has a lot to do with it. That's why I think a cleaning couldn't hurt.

 

[67 coronet]

take the top off and look inside.not tuff to do and you shouldnt break any gaskets.will let you see any dirt inside and allow you to clean it out.also,check the accel pump plunger(comes out with top)prob bad due to sitting and may be causing your stumble prob.rebuld kits are pretty cheep and wouldt hurt a bit to do.simple carb and very easy to rebuild.just keep track of how and were each part comes from durring disassembley to alow for easy reassemble if you have never done a carb rebuild before.

 

[coloradodave]

In addition, disassemble it on a nice thick towel so that you capture all the parts. Pick up a couple of cans of spray carb or brake cleaner, remove all the parts that are screwed on, and blast the cleaner through all the parts and little passages you can see. If you have a compressor and an air nozzle, blow through all the passages. Pay particular attention to the accelerator pump discharge nozzles (center of primary bores with 2 little brass tubes pointing into venturies). Then while you have it apart, check the float level and drop. Edelbrock has all this info on the web, even a you-tube video on how to disassemble, do the adjustments, re-assemble and tune on the car.
It's easy, just take your time and ask questions here if you get stuck.

 

[AAXD530]

I'm going to go for it. Soon as the snow flies I will tear it down and clean everything. It has to help. Thanks for the advice.