Car runs way too rich at an idle, maybe all across the rpm range, too. I'm talking burn your eyes kind of thing; always has, I've just never felt comfortable/knowledgeable about dialing in carbs/timing/plugs,etc. So I've let it run "rich" assuming I was erring on the side of safety. But no more! Time to confront my fears! Here's my combo: '72 340, 1.88 j heads, 8.5 +/- comp, .474 lift/228 deg @ 50 cam, hooker super comp headers. 4 speed car. Ignition is MSD 6al, stock dist (w/15 deg adv. plate and orig springs), rn12yc champions gapped @ .045. Idles about 900, 13" vac, timing is set at 12 initial, 38-40 total at about 3500(I know that's probably too much- I'm either going to order FBO's plate & spring kit or weld up my slots). Carb is stock from the box (9 years ago).I don't have an A/F meter and I'm a bit nervous about getting the thing too lean. My first impulse is to step up the "big end" of the metering rods (71 to 73 to 75) but leave the power size alone.Good idea? Could a plug heat change help? What do I need to watch for/look at while I'm doing this? As stated above, it's been this way for years; I'm just tired of making excuses for why it doesn't seem to run right!

Eye burning fumes can be from too lean a carb also. How have you got the air fuel mix screws adjusted?

I set the idle screws the best I could (rpm & vac), but with the rumpity-rump it's kind of hard to be positive. Backed out about 2 turns from closed. When I pulled the plugs, the bottom threads were wet & smelled like fuel. I'd have to pull them again to tell you any more than that, tho.

Check the float levels!

Hey, I woud first check the Jets. I have messed with AFB's, AVS' on my 71 440 cuda in the stock class.....Typically the new afbs/avs/edelbrocks come way over jetted. With the bigger cam you run, idle screws are not so important...crank them out so it idles decent. THey quit working anyway once you give it some gas...
IF you run Qt mile or street, how do the plugs look after a run?

I would keep 4 side square on jet size. They seem to run better that way....Curious to see what you jet sizes are right now....I have some base figures on jet sizes I can give you (from experience)

If the car runs great otherwise on the street, plugs look good--you can fatten the metering rods so it decreases the jet size hole at idel...those lift out of the hole as well once you hit the gas.....

If your plugs are jet black...probably too big of jet sizes...

I have gotten a puny 750 AVS to go 11.8 on my 440 with cast iron intake...

Let me know, Jeff.

Jets are supposed to be .098 primary, .095 secondary (according to info I've found); I'll pull the top to make sure & check float level per Dodgem's post.Just want to make sure I can get a new gasket today before I start,in case I can't re-use the old one.

make sure the metering rods are staying down at idle and not bouncing. run engine at idle with rod covers off and see. Use a lighter spring in there if they aren't held down at idle.

try opening the gap a to .050. thats what MSD recomends for cars with less than 10.5:1 compression

You can reuse the gasket over and over again..I do...unless you rip it obviously....Gas doesnt get that high in the bowls....

-is your carb an original? or aftermarket federal/edelbrock?

098 /095 is about right for stock 340 carb....
factory settings always had smaller secondary jet...never bigger...

You however are running bigger cam and headers...that will automatically lean out a factory setting carb....How do your plugs read?

Check your jets --the numbers are on them..or take numbered drill bit to check....

You want more HP for your set up? GO to a 750 AVS or AFB....(they dont actuall flow 750 cfm but less)..You will keep same gas mileage and get 10-15hp boost...You are running too small a carb for a hopped up 340...

That's what I always thought,too. But I just pulled them out & measured them, .098 primary,.095 secondary. And the float level is right on spec @ 9/32, per Dave Emanuel's book. The springs look more pink than orange(stock app. from allcarb.com's site),but they're definitely one of the two. Anything more I should do before I button this back up? Man, I type too slow. It's an aftermarket carter competition from Federal Mogul before they quit making them. Drivability is key right now, as this is mainly the wife's car, but I do have a new comp. 750 AFB I could swap in. Figuring how to read plugs is next on my learning curve.

With your set up and stock carb--it actually looks lean...
..does it idle good or do you need to kick it higher?
you should be able to run .098 at all 4 corners.. and still not be rich...

_if your plug looks pretty white....you are too lean on the jets....a nice darkish brown--and even slight black around the ring of plug--and still not be too rich...if this takes a high idle--then increase primary jet to .100 or 101...and secondary to .098...

pull a plug before putting on the top...

I take the top off between races to change jets if necessary...

If your plugs look black....Switch to a .095 primary jet--and stay with a .095 secondary or drop that one to .089 or so...
-It becomes a "dialing it in" issue with primary jet--and keep the secondary number close to it...

With 8.5 compression....it may need to be leaned out....PLug reads tell the story...

burn your eyes kind of rich I'm thinking:(1)need weaker metering rod springs (2) floats (level/pinhole). Holler when you find it. EDIT what do your plugs look like? I'd get a strip kit & toss in the weakest springs & you'll know in 2 minutes if that's it. MORE EDIT No strip kit? Take the springs out completely & idle it. You'll know in less than a minute. I'm assuming that you dont have too much fuel pump psi @ idle, eddys cant take much.

OK then,here we go. 1, I pulled the plugs & they are all dk brown to black w/ coloring on the insulators. Damp/wet around the bottom of the threads. Note: the Chall has not been driven for months, only run in the garage to test & tune this past week. After I get it running today it'll get a good wringing out. Maybe show something new? 2, I'll gap the plugs to .050 before reinstalling. 3, I'll pull the metering rod cover plates @ idle to check operation. 4, a friend of mine has several strip kits, so I have access to different rods & jets. 5, get my distributor fixed up so timing can be set correctly. 6, move the 'puter out to the shop.Too much walking back & forth.

Rereading your post if you have a genuine carter competition series AFB it would be jetted on the rich side plus possibly an altered idle circuit but I sure wouldn't think eye burning rich. If you toss the springs for a check do replace the flat covers then idle it and I'd glass bead the plugs or get some new ones. Fuel pump psi is not excessive correct?

I don't believe the fuel pressure is excessive- I'm running a carter mechanical pump (one of the ones that bolt together), but again not sure of psi. I checked the rod plungers/springs, they're pulled down at an idle. I gapped a new set of plugs .050 & installed them- it actually seems to be a little better, odor/smoke wise. And a bit snappier when I blip the throttle. Only concern is they are rn 14 yc plugs, and I don't want to run too hot. I'm going to go get a new set of 12s right now & try them,too.

What part of Oregon are you in? I know some quality tuners that could help you out.

as noted above...check that the metering rods are staying down while it idles..

step up springs could be too stiff.