I have my edelbrock carb jetted almost stock and I am at 5500 feet. The air/fuel gauge reads just barely rich and goes in the middle at light throttle. The next step leaner seems too lean it's always in the middle or in the lean section at part throttle.

Also where should I put the secondaries?

1405 carb
primary jets are .100
primary rods are 73x52
secondaries are .095

 

The old phrase is "leaner is meaner, but it makes more power."

The only thing I can suggest is that you do any tuning changes from this point AT THE DRAGSTRIP. You have obviously spent some time dialing it in with the O2 sensor. The only observation I will make is that every combo is different. Some engines want to be richer at WOT. Some want to be leaner. It's all over the map, really. You're probably pretty close. At least you're not pegging the scale or anything obviously wrong like that.

An engine accelerating quickly through the gears is a very different animal than one making max power at a near-constant RPM.

What it boils down to is: it's damned complicated to eek the last few tents/MPH out of a combo once you're really close. You have to try stuff and see what it responds to. It may want to go squeaky-lean for best times. It may want to go almost pig-rich. Make changes ONE AT A TIME in SMALL INCREMEMENTS. Write EVERYTHING down. You are guaranteed to fail the memory test on this one after 3-4 jet/rod changes.

 

BTW- Edlebrocks (and Carter AFBs) are unique animals. You can get rods with varying cruise and power tip diameters. For any WOT tuning I'd concentrate on the rod's power tip diameter for making any changes to the A/F ratio. Your part throttle A/F ratio sounds really good. The last thing you want to do is mess that up.

You have 73/52 rods in there now. That means it's .073" on the fat part of the taper (part throttle) and .052" on the tip (WOT, power-enrichment mode). I'd try a set of rods that has the same .073" big diameter but see if you can find a set that's got a tip diameter that's either richer (smaller) or leaner (larger) than .052"

I'm no Edlebrock guru by any stretch but I think that richer rods (with a smaller tip diamter) are readily available, but going leaner on the tip...... I don't think you can go any leaner if I recall my Edlebrock rod specs. That's when you want to play with the SECONDRY jets. They really only come into play when you are very close to WOT- when the seondaries start to open. As such, that's probably where you will end up making most of your changes to WOT A/F ratio.

QJet carbs are simiar in their weirdness. They respond well to very rich WOT mixtures on the primary side so cover up the "hole" that happens when the secondaries start to open. From there out they want to be rather LEAN on the secondary side. End result is crisp response when you first mat the pedal and good top end pull when it's really "laid out" all the way.

 

Thanks alot! I just installed my LT4 hot cam yesterday and I am waiting for my new disributor gear from GM but I plan on tweekin the carb as soon as I fire it up.

 

In my opinion, Move to or race at a lower elevation! I used to race at a track that was close to 1mi. high with low humidity and baro. pressure. Even the pro's when they came to our track, had a problem and got their butt's whipped by the locals who had their car's dialed in. When I went to the west coast( lower elev. higher hum.) I beat cars that I never could at the mile high track!
Ox content at high elev. is lower than sea level. Eveything changes at high altitude. Humidity, baro. pressure, and temp.
After time trials in the afternoon I had to dial in .010 faster for eliminations in the evening after the sun went down or I would break out of my braket!