Thread: way richer, plugs still look lean

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Originally posted by DennyW
Looks like it's getting to hot (lean). Correct this right away.

cid x max rpm divided by 3456 = CFM
The 402 with a hyd. cam that carries a max rpm without float @ 6500.... doesn't matter that you decide to run it at 5000, or a 650 if you want, as long as you can achive enough cfm to stay away from lean burn.
You posted that you've already reached the next to max with the carb that you've got- that put's you at about 670 now & still too lean- I guess that after you reach the max on the primary side you can - I dunno, hog it out.....or rework the venturi's- good luck with that one, or get a carb with larger primary's.

you'll are talking 5,000 up rpm. the(way i read it)he is just driving it normal and at idle and should be able to run a 2 bbl. without burning the plugs up. am i reading it wrong?

I also agree with LS1.
I thought by using a smaller carb it would HELP the streetability.
I would think that a smaller one would create better pressure drop in the venturis and therefor pull harder on the jets and pull more fuel.
Obviously this isn't working out as planned or I wouldn't be posting this problem.

Originally posted by tcodi
I also agree with LS1.
I thought by using a smaller carb it would HELP the streetability.
I would think that a smaller one would create better pressure drop in the venturis and therefor pull harder on the jets and pull more fuel.
Obviously this isn't working out as planned or I wouldn't be posting this problem.

if all you are doing is normal driving and you are heating your plugs up then you have other problems. I can pee enough gas to ride around on . how hard are you running it ?

I was having some fun with it, but nothing crazy.
just some hard pulls out of some stop signs and maybe
up a couple hills.
I still haven't even given it full throttle though.

Originally posted by tcodi
I was having some fun with it, but nothing crazy.
just some hard pulls out of some stop signs and maybe
up a couple hills.
I still haven't even given it full throttle though.

I don't know, but I doubt you are running out of cab.

k

Fatten up the jets on the primary side by 0.003" to 0.005". If the motor isn't surging (changing rpm's up and down on its own) in cruise mode, then it isn't too lean, but try the fatter jets just to see what happens. I know you've been changing metering rods, but try jets.

As far as carb size, you are right on the money with what you intend to do with the truck. You'll get great throttle response and manifold vacuum with smaller primary venturis.

i thought on you had to change the metering rods with the jets at the same time to properly adjust an edlebrock? or could i have always just been able to swap out the metering rods and be done?

No, you can change either or both. I'm just thinkin' that he's probably gettin pretty thin on metering rods and might have some more flexibility if he changes to a fatter jet.

yep, you can change either the rods or jets, and you are correct, I am pretty thin now on rods. I have some new jets that are .003 larger that I'm gonna put in tonight.
It isn't surging or anything in cruise though, nor was it even before I went richer.

Originally posted by tcodi
yep, you can change either the rods or jets, and you are correct, I am pretty thin now on rods. I have some new jets that are .003 larger that I'm gonna put in tonight.
It isn't surging or anything in cruise though, nor was it even before I went richer.

if you haven't gone to a bigger jet before, then i believe tech. is right.

just for reference this was the plug before I richened it up a few steps.

one thing I wanted to check on is the large tube connection on the front of the carb that I think is for PCV. I had the carb off last night and saw that this tube has a passage that leads below the throttle plates.
I had it hooked to my valve cover breathers, but wouldn't that line suck with full manifold vacuum on the breathers then?

There is a very similar connection on the rear that I have hooked to my brake booster. But both have passages leading under the throttle plates.