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-   -   tuning edelbrock carb for 440 (http://www.moparchat.com/forums/showthread.php?t=112045)

my70superbee440 08-12-2008 11:09 PM

tuning edelbrock carb for 440
 
iv got a 600cfm edelbrock carb on my 440 seems to be running way rich when 4bbl is in

dwc43 08-13-2008 02:24 AM

Well, first off the carb is wayyyy to small. The stock Thermoquad for big blocks are 850 cfm. Heck it's too small for a small block for that matter. Only thing you can do is adjust it and lean it out till you can get a carb that will work on it. You'll see one heck of a gain in hp once you get the proper carb on it. :)

lazarus 08-13-2008 04:44 PM

What is your timing set at? Initial and total. Do you have a fresh tune-up? Plugs, points, cap rotor wires, etc. The 600 is small, but it should run fine.

wilks3 08-13-2008 05:26 PM

I've got a Eddy 600 on my .060 over 440, runs fine for how I drive. You couldn't get the plugs to look any better. Sure it loses at wide open over a 750 or 850 carb but I don't drive that way.
Mild Comp cam, HP manifolds, 2 1/2" TTi X-pipe system. After alot of sorting out, 25* initial/ 10* mechanical/ 15* vacuum timing. A true 9.3 to 1 compression ratio. Eddy carb has stock jetting and rods, but 1 step heavier rod spring.
......and it still runs pretty good too.......ask the guy with new red Hemi Charger who had to see if the old black Charger was fast......after I slowed down and he caught up he just shook his head and drove on.

my70superbee440 08-13-2008 06:39 PM

had a guy set the timing when it was painted think he said 2.5 ptc new tune but plugs are black i put an eletric fuel pump on it and has a clear filter but it only get about 1/8 full when car is running that sound right

wilks3 08-13-2008 07:22 PM

The timing should be at least 15* advanced, and work from there.
How much pressure is the electric pump putting out? If over 5 lbs. you need a regulator to control fuel pressure. Sounds like too much fuel pressure for the
carb. The clear fuel filter will most always have some kind of air bubble in it.

my70superbee440 08-13-2008 10:43 PM

not sure what the pressure is on the pump it can off of a 1970 440 cornet that i allso have think i might just hook up the old pump the cornet just seemed to start easier the the bee thought to electric would be better lol iv always just turn the timing tell the motor turned or good guess i need to buy a light and do it right how can i get more air to the carb and whats the diffreance in 600cfm and 750 just bigger jets ??? i thought if its flooding it needs a smaller carb thanks for the help

dwc43 08-14-2008 02:55 AM

I have to agree with Wilks on this one. He's close on the timing and the old edles don't need more than 5 psi of fuel pressure. If you're running and electric I'd guess you are way over 5 psi. You need to get a gauge and check it. Junkzone sells them for around $20. They go right in the fuel line and you want it place it between the filter and the carb cause the filter causes a slight restriction.

You need a dial back timing light to set the timing correctly. And make sure to disconnect the vacuum line on the advance when setting the timing. You really don't need it on a performance car anyways. And most stock ones put in too much timing.

600 and 750 cfm has nothing to do with jets. It's how much cubic feet per min. the carb can flow. Then you change the jets to get the right amount of fuel to air ratio. A stock 440 needs at least and 800 carb. The stock Carter Thermoquad on the 440 was 850 cfm. You're starving the engine of both fuel and air. Your other post said it feels doggy and this small carb is why it feels doggy. Even when your carb is too small it can be jetted to the point it's too rich and putting too much fuel into the engine for the amount of air it's getting. :)

rumblefish360 08-14-2008 09:11 AM

Early years on the 440, 600 cfm Carter AFB's were stock. It's enuff for mild manored driving. The 85- T-Q's were stock in later years and put on the cars/engines because they were the new design that also fit the bill for racing catogoreis that bennifitted from the larger carb.

Just because 440's came with 850's dosen't mean they should all have it or show a big bennifit from it. Most T-Q equiped engines were low powered smog engines anyway.

You need a timing light to time the engine right.

The difference between the 600 and 750 carbs are throttle bores and butterfly sizes. The jets in the 750 are also richer. (Larger)
A few horse power on the big end. Loose a few #'s of torque on the low end with a squarebore, not really so with a T-Q due to the spreadbore design.

On the 600, you'll need to make the jets smaller to lean it out and start with small changes.

The clear fuel filter shold not be glass for saftey sake, but 1/8 filled is not enuff. There should be about an 1/8 left in the filter of air.

I would re-use the stock fuel pump and run it with new plugs. Then go to leaning it out

my70superbee440 08-15-2008 01:30 PM

if the electric pump is to much psi will that load up the car at an idle ? it used like 3 gallons of gas just idleing in like 20 mins and its running hot now

pishta 08-16-2008 12:17 AM

Tuning an AFB, always start with the rods. Much easier, you can do it while it is idling (almost) and it doesnt require the carb top to be removed, just 2 screws and a few clips. Bigger (fatter) rod leans it out.

rumblefish360 08-16-2008 02:06 AM

Quote:

Originally Posted by my70superbee440 (Post 746561)
if the electric pump is to much psi will that load up the car at an idle ? it used like 3 gallons of gas just idleing in like 20 mins and its running hot now

If the pump over powers the floats, it will sooner or later fill up the carb and spill out ontot he engine.

A high float level will have the car run rich.

pcrmike 08-16-2008 08:25 AM

I have to agree with the Fish here. Also, I ran a 600 on my tow 440 while I had it and sold it to a bud of mine 12 years ago, and he still has it. Gives great mileage, up to 16 on teh highway. I had it for pulling my RV. :-) PCRMike

dwc43 08-16-2008 12:15 PM

Quote:

Originally Posted by my70superbee440 (Post 746561)
if the electric pump is to much psi will that load up the car at an idle ? it used like 3 gallons of gas just idleing in like 20 mins and its running hot now

Yes it very well can if it has enough pressure to keep the floats open in the carb. The edel only needs about 5 psi. It just can't handle much more than that without flooding the car. Get a gauge and install it between the carb and the filter and check it. :)

Dave 572 08-16-2008 06:34 PM

First off, I'm assuming your carb is similar enough to the 800 AVS I had.

I may have missed it in the posts, but what is your vacuum at idle? Eddy carbs don't like less than 7" of vacuum. Should not be a problem with a carb on the smallish side such as yours.

Loosen the covers that hold the metering rods in place so you can see what they're doing at idle. If they're bouncing, you'll need to put weaker springs in.

I hate to suggest this, but if you went through that much fuel at idle there may be a chance you washed out your rings. You'll know if this happened when you drive the car. Take it up to 5000 rpm or so, and let it coast down with your foot off the throttle. You'll see blue smoke in your rearview mirror. DAMHIK. A leak down test will further confirm it. Check your oil to see if it's contmanated with gas.


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