Fuel Mixture

[etxshadow]

Hey I have a 302 w/ edlebrock 600 sittin on a performer intake. she has .86 jets in her and i am at a los on what to do next. any suggestions?? b-(

 

[Seabronc]

Your carb should have come with the idle mixture screws preset. If you haven't played with them, you might not have to touch them. The standard Ford Holley has them sealed, but I believe they are acessable on your carb. They are for idle mixture only, so if it idles properly, I wouldn't touch them. The adjustment is a bit of a proceedure and should be done with a TAC and vacuum gauge. If you want to get max performance out of it and don't know how to make the tweaks, I would let a pro do it. If you don't know what you are doing, you can do more dammage than good.

There are several things that need to be done in sequence so you don't mess up the next step. ie. proper timing, idle speed, etc.

I'm not suggesting that you don't try learning but be sure to do a little research ahead of playing with it. If you are in a hurry, go to a shop.

If you do a google search on carborators, you will find more information than you care to know.

Good luck,

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[BLUEovalBELIEVER]

86's? that sounds alittle too big for a 302.is the motor stock?the easiest way to set the idle mixture screws is to slowly turn them in till they stop,don't crank hard on them just turn them in till they stop,put a mark on the screw and the carb and turn them out 1 1/2 to 2 turns each(turn them both the same amount,now hoping that you have no vac leaks and your float and timing is on hook a vac gauge to the INTAKE MANIFOLD not the carb start the truck and adjust until you have a smooth idle and the most vac.that's the good old fashioned way i guess it's always worked for me.
if you get erradtic flucuations in the vac needle you have some other probs,call edelbrock or buy a book it'll tell it all to step by step.be careful though you'll be leaning over the fan and long hair and loose shirts are a fans favorite food.
sea is right after idle those screws don't do diddly hench the name idle mixture.
i'm not to familiaer with edelbrock but have worked on a few,a little rich is better than a little lean,lean will burn a hole in a piston.check your plugs after awhile and go from there.those books have a plug page in them to help you see how your motor is running.

 

[orich]

Like the other post said 86's are way to large unless your racing it. I would put in about #62-66 then adjust mixture air/fuel 1-1/2' to 2 turns out. Read the spark plug color for rich or lean mixture Also check pump shot nozzle #jet size smallest is #25 for best gas mileage plus you may have to change pump shot cam. If you don't know what i'm talking about it's time to learn. Get a copy of holly carbs. It's the Holly bible. If you want to know what your doing and how to rejet and tune and so on.. my 2 cents..
orich

 

[Seabronc]

Yah, I agree with orin, but since you have an Edelbroc, I'd get a book on Edelbrocs. However, if you plan to switch to a Holley 4160 get the Holley book.
He is right, carbs aren't as mysterious as some people think. I've had more problems with the things outside the carb causing the engine not to run at peak. Vacuum system components have effects that can be confused for carberator problems.

Good luck,

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[Bear]

I've tried many combos for my 76 w/ a 302. The best fit was a Edelbrock 500 carb on a performer intake. My 600 was to much for it and it was running to rich. I put on the 500 and my response & perfprmance improved big time and haven't replaced a plug in 5 years.