Carb size?
Cross-Country
Joined: Dec 2015
Posts: 92
Likes: 0
The reason I think too much carb hurts driveability is intake air velocity. Carbs work on pressure differential. Bigger carb(Venturi), less velocity, less emulsifying and atomization of A/F. Lost efficiency.
Ps. don't forget about your ignition system.
Will
Ps. don't forget about your ignition system.
Will
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Fleet Mechanic
Joined: Dec 2012
Posts: 1,257
Likes: 1
From: Scottsdale, AZ
Played around with the air/fuel mixture screw on the edelbrock today. Runs a little better, adjusted the accelerator pump to the leanest position, and received the air/fuel ratio kit today from summit. I'll install that hopefully by the weekend, and see where I'm at... To be continued...
Post Fiend
Joined: Apr 2002
Posts: 19,311
Likes: 97
From: Waterloo, Iowa
For you guys running the air/fuel monitors how do the plugs end up looking at the ideal ratio? Are they leaner looking in appearance than you would have otherwise run, without knowing for sure?
Posting Guru
Joined: Apr 2013
Posts: 1,170
Likes: 2
From: Rimrock AZ
The only way I "knew" the engine was rich was just a feeling by the sluggishness of the throttle.
Logistics Pro
Joined: Nov 2011
Posts: 4,685
Likes: 81
From: Northville, MI
Played around with the air/fuel mixture screw on the edelbrock today. Runs a little better, adjusted the accelerator pump to the leanest position, and received the air/fuel ratio kit today from summit. I'll install that hopefully by the weekend, and see where I'm at... To be continued...
Here is an "old school" chart that should help you. You need a vacuum gauge but they are cheap at most auto parts stores.
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Fleet Mechanic
Joined: Dec 2012
Posts: 1,257
Likes: 1
From: Scottsdale, AZ
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Tuned
Joined: Mar 2014
Posts: 319
Likes: 18
Carburetion
Have to agree with the majority, 750 cfm is too big for a 350 ci motor, unless it's on a NASCAR motor. Cam specs would help. That's the 2nd most common problem building a performance motor. Do LOTS and LOTS of research, and read every automotive article you can. Best of luck, lots of good folks on this site willing to help.
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Fleet Mechanic
Joined: Dec 2012
Posts: 1,257
Likes: 1
From: Scottsdale, AZ
Albuq,
I'm wiring my MTX-L right now, where did you run the red power wire? "isolated 12V switched power source".
I'm wiring my MTX-L right now, where did you run the red power wire? "isolated 12V switched power source".
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Fleet Mechanic
Joined: Dec 2012
Posts: 1,257
Likes: 1
From: Scottsdale, AZ
I found a yellow/black wire that is an accessory wire. got the gauge wired and sensor is calibrated. now just need to go get new exhaust gasket. finally get to see if i'm running rich/lean.......
Tuned
Joined: Oct 2016
Posts: 255
Likes: 2
From: South dakota
Carb Jets
Carburetor jets are marked in motor craft auto lite carbs numbered. What does the numbers mean? I have a 55 jet in mine and was told I can run a 62 or 64 jet? The engine is a 1973 390 in a F-250 4 speed manual. My carb is a stock Motorcraft carb 2 barrel. It had #55 jets in it I tried #64 jets and seemed to rich so backed off to #62 jets What would be correct? Oh and when I rebuilt this engine I installed a RV cam. Would that cause it to want more Fuel?