Alessandro wrote:

RV6 wrote:

Alessandro,
Here is the A/F chart and the numbers you should be seeing. I looked at the edelbrock manual and having no experience with their carbs it's greek to me. What carb are you running?

Thanks , i am running a 500 cfm edelbrock with electric chocke (classic 1403 )  . Now is setted at 10% lean as edelbrock chart suggest with rods and jet . 
What happen :  start car and idling number varied from rich to middle .  When riding the numbers are always on 10 except when release the pedal that start changing . . 
what i can do ?  sound strange that the little 500 cfm needs to work at 10 % lean ? 
I have debate a lot between 500 and average American choice on 600   for a stock 289. 
I am worried to understand that i need a 390 cfm to run this engine ... Sounds correct ?
Thanks 

What elevation do you live at. The charts are set up for sea level and most likely a 350 Small Block Chevy. 10% lean at sea level is probably to rich at 3000 feet. I am currently running the Summit MO8500VS, a 500 CFM carb, and have no problems leaning for elevation. I always laugh at "Ready to Run out of the Box" advertisements as they may work at sea level but not at 8500 feet where I live. Plus, they're marketed towards Small Block Chevy's and not our little 289's. 

Drop a needle and jet size and see what happens. Your A/F meter will tell you. You may also find the power valve (if it has one) needs to be changed also. Do one at a time, check the A/F and change as needed. 

Once the A/F ratio is dialed in you'll be surprised at how much better it runs. 
 

Last edited by RV6 (4/29/2020 2:00 PM)

TKOPerformance wrote:

Edelbrocks don't use a power valve.  I recommend going one step at a time.  There's another half of that chart that shows what the numbers correspond to in terms of jet and/or rod changes.  That's important as it only covers a couple models of carb.  They are set for cruise and power.  Acceleration enrichment can be added by altering the pump shot (three possible positions).  I've found no benefit or need to mess with the step up springs unless running a radical cam. 

I've never used an AF gauge to tune a carb.  I set it initially by leaning it out until feeling it surge, then go back one step richer.  Beyond that I like to tune power on the strip.  The biggest thing is weather though.  I can tell it leans out in cold weather at all points indicating it would run better if I went one step richer, but I typically just drive it a little more carefully in the cold to avoid hurting anything.  One day EFI will solve those issues. 

I don't see anything being "ready to run" out of the box at that altitude!  You're really up there!

The elevation is not a problem , although i will tell because i know is a part of the game . But i live more or less at sea level (  100 feet ). but i can go on top of mountain in one hour at 6500 ft  . . 
Please can you tell me which is the other page you are talking ? can  you give me that one ?
I do not have any lower position charts ,
i am already at lowest lean possible ref nr 10 ( that means 12 % lean ) ..
There is any other solution to know if sender is working correct ? 
What i can do is downsize the squirters from 31  to 24  -  For rods and jets i need to buy little of both .  
Thanks 

TKOPerformance wrote:

Been having issues posting pictures lately, but thins links you to it:

https://www.manualslib.com/manual/42643/Edelbrock-Performer-Series-1403.html?page=19#manual

Thanks tko , this is what i am using now . More than 12% lean you can not go with this chart. 
need  to go leaner than now . Asked to edelbrock 

some news comes out from edelbrock talk . Just a change in the squirters from 31 to 24 and magically the afr comes working again , and with a right move through the range . Numbers are always changing , but when i try to cruise regular they move to 13 to 14 , more or less between the stoich range .  Car goes really nice and powerful , without esitation or stumble . no more smell of gas.  I think i have found the right spot , but i can confirm i am using the leanest match on edel charts . I can be sure only testing on professional tester from a shop - Maybe i don't need going lower than now but i am still curious what can happen only 1 step more lean .