Eddy carb reccomendation

[sleepychallenger]

man I only get 2.1 miles to the gallon in my 18 gallon tank..... 

goody the wiring has been cleaned up as thats an old pic 

but yours is by choice. im trying to make mine better. mine even went down after i put in the electronic ignition, i was getting 10 mpg before

[Rob C]

I agree with the 650 AVS. The 383's came with the small Carters back in the day and there around that 600 for the AFB's and 630 cfm for the AVS.
You can pick up performance with a 750, but with your stock running gear, I would not bother.

[Chryco Psycho]

I disagree ,the 750 AVS is a vacuum secondary cab & will not over carb or bog the engine + it is far more adjustable then the afb crap + n it will not limit max power , being a muscle car why limit the power ??

[Rob C]

Chyro, this is why I think a 750 is something I would not bother with.

i am running 323 gears with a stock 727 tf. the 383 has a hemi grind cam and a .030 overbore. thats it. MP electronic ignition.... in town driving but in town is about average of 50 mph.

 I used italics to high light the key area I thought of concern.

Now I'm also makeing this recomendation on a assumption that the OE poster may not be able to tune a carb well. Be it the case or not, the larger throttle bores can be harder to tune in. A smaller carb will be very responsive to throttle position, the engine will indeed pick up power with more cfm's, but not really use/need them until higher RPM's  which seem not to be the case with low MPH speeds. With the 3.23 gears, even a small tire car will not turn alot of RPM's.

At 5,500 rpm's, a 383 will need about 600 cfm's of carb, at 6000 rpm's, about another 50 cfm's.
A lightly modified engine as his could use some more cfm for max performance, but I didn't think he was after that given the basic set up and low speeds he stated he drives at.

AVS 650 or Holley 670 would fit the bill IMO. But thats just it. An opinion. 

[GoodysGotaCuda]

Absolutely, the more cfm you have the less velocity there is in the intake manifold and the more volume of mixture is availible. Which is great for spinning it up to high rpm. To keep a more torquey setup for inteded low rpm and high gearing, the smaller cfm rating will allow for higher intake charge velocity making low rpm torque.

650avs. Easy to tune. Holds a tune, will perform well in his situation. Same carb feeds my hoopty 318 to 6000rpm and moves my 3600lbs through at mid 13s. It's about maxing the carb out with the low gearing/high stall i have, it'll be in its prime on his engine.

[Rob C]

Mike, your right. However, if one can tune in the carb, a 750 isn't so bad. I would rather it with higher gears and such.
I have a Carter 750 on my 1978 400 cid engine with a 727 and 3.55's spinning 235/60/15's. I'l be making a change to a 625 later.

The 625 has smaller primarys and larger secondarys when you flip it over, you'll see. The smaller/restricted primary size make it snappy.
I'm no great carb tuner, but the 750 isn't what I like on top of this 400. I think the biggest problem is the 400 is lame in power and anything needed for power. Just to much carb for the whooopppin 200 HP it came out with years go in the nasty power robbing smog era. Heders help abit, nothing to get crazy over.

[sleepychallenger]

update. I put on an eddy 1406 tonight. bit of a pain and learned something too. That choke stove, very important to bolt the plate back down after taking the other part out. sounded like a drag car with a valve bouncing around when i started it.  on to the more serious stuff. i am pinging again and the carb just doesnt seem to work as well at full throttle, like the secondaries arent opening or something....  however, the car doesnt diesle when i shut it off and the surging at idle while in gear went away. it is also more responsive on take off and starts up much easier. also seems like i have more vacuum for the brakes to run off of because they worked better all the sudden. a lot of good compared to the bad. i think the pinging is in the timing. i will check that tomorrow but i was running 51 degrees total advance which i was told was way too much. i was told that total i should be around 30 - 34.  not sure where the power went though. i went from a 630 cfm to a 600. didnt think it would be that much of a difference. i also have not hooked the choke up yet. definately some stuff to look into before i park her for 4 months on saturday. any help is greatly appreciated. if anyone is running one of these on their big block, please post pics as i had to do some "modification" to make it work properly.

[Jacksboys]

I know that my 360 is not a big block, but it should be close to your 383.  I did have to richen up my carb a little.  These carbs are setup for economy so they can be a little lean.  Also your timing should be set with your vacuum disconnected and should be in the 30 to 35 range.  When you reconnect your vacuum hose, then take a second reading to see what the timing is.  If it is pinging with the hose connected, you can adjust the amount of vacuum advance by using an allen wrench in the vacuum hole of the distributor.  I do not remember the size but others should know.  Hope this helps 

[sleepychallenger]

with the vacuum advance disconnected, i am running about 15 degrees. with the advance hooked up and full advance, i am running at about 51. i think i need to use the allen key to turn the advance down. 

[Jacksboys]

with the vacuum advance disconnected, i am running about 15 degrees. with the advance hooked up and full advance, i am running at about 51. i think i need to use the allen key to turn the advance down. 

What is the RPM when you reach 15 degrees disconnected?  If that is your total advance without a vacuum (around 3000rpm), I can see why your motor is losing power at full throttle.  If you turn down the vacuum advance a good bit and then advance your non-vacuum up to a total of 30 to 35, the engine should have a bunch more power at full throttle.  If possible I would keep the total advance with vacuum under 50 degrees, but it really depends on what your engine can handle.  Good Luck 

[sleepychallenger]

that is at idle. maybe 900-1200 rpm

[Jacksboys]

that is at idle. maybe 900-1200 rpm

If you are at 15 degrees at idle, that is your initial timing, and you need to find out what the total timing is without the vacuum.  So with your timing light attached, rev the engine up to around 3000rpm and find out what the timing is there.  This will be your total non-vacuum advance.  It should be around 30 to 35 degrees of advance.  If this is not the case, then adjust the distributor so that the total is in that range.  Leave the vacuum off and take it for a test drive.  Also make sure the carb vacuum hole is plugged when you drive it.

If you like that setting then, turn down the vacuum advance on the distributor and plug it back up.  It should be under 50 degrees.

I hope this works for you. 

[sleepychallenger]

i will have to give that a try. maybe i will have time before i leave. getting short ya know

[Mopar73340]

with the vacuum advance disconnected, i am running about 15 degrees. with the advance hooked up and full advance, i am running at about 51. i think i need to use the allen key to turn the advance down. 

If I'm reading your timing #'s correctly and you have 51* AT IDLE with the vacuum advance connected, then you have it connected to the wrong port. It should be on the ported vacuum port which should have NO vacuum at idle. It is on the pass side of the front of the carb.

[Moparal]

Sleepychallenger has no tach hooked up in his car. When he was over my house, we put the carb on a vacuum gauge and adjusted the best vacuum and lowest idle. Can't tell by ear, but his idle was prob close to around 750 maybe a little less. Checked the timing and set it at 15 degrees with the port unhooked. Rev'd it up and it came to 35/36 degrees. Then hooked the line up and it came to 55. Then I put the wrench inside the vacuum advance and turned it about 10 full turns. Got it down to 51 degrees. It has low end response very good now. It has throttle response anywhere in the throttle when you accelerate. It does not ping now or diesel when you shut it off.  This car has not been jetted in the carb. It has a hemi grind cam with stock exhaust and a single legger 323. I was doing really good for a factory carb,gears,intake and exhaust plus bigger mufflers. He won't get much more out of it performance wise untill he does other mods. He picked up 3-4 mpg just what we did without going into the carb. A hemi grind cam is not a big pulling top end cam in a 383 with a stock intake and 323's. When he is ready to make it a street blaster, all's he has to do is drop by. We can toughen it up as much as his wallet allows. He may have a control box not worth a crap far as I know. Some mopar boxes work better then others. It has an orange box out of the kit it came with. But doesnt seem to burn the fuel as good as his point distributor. Hadn't checked the coil either. Points to electronic, I think there was a difference, can't remember