Edelbrock 1407 lean at WOT

[ohitsjustbrian]

Been banging my head on this for awhile now, I have a mild 440 with secondary metering jets 3 stages rich (.116" jet) and still reading high 14s AFR at WOT. Cruise reads around 13.7 and Power Mode is upper 12's, the calibration is below. I'm not sure where to go from here as there is no Richer setting I can even use for either the primaries or secondaries. I guess I could have a massive vacuum leak but I'm getting about 10 hg vacuum at idle so I don't think that's it. Any input would be appreciated.

Note: I did order the high-flow carb needle and seat. It arrives later today and ill update this after I install and test it.

Calibration:
Primary Jet .116" Rod 0.065" x 0.037"
Secondary Jet .116"

 

[RemCharger]

Make extra sure there's no leaks in the exhaust before the 02 sensor

 

[GTX JOHN]

There is something out of sorts. Maybe a undetected vac. leak or pressure
issue.

That is richer than I run (.113) in my 440 race car.

 

[lewtot184]

Check fuel pressure and try a volume test. Hooking up a fuel pressure gauge and doing a WOT test would help. Probably not a carb problem.

 

[ohitsjustbrian]

Make extra sure there's no leaks in the exhaust before the 02 sensor

O2 sensor just behind collector and it looks good. Just pulled a spark plug to sanity check as well. I'm not great at reading these but this doesn't look super rich to me

 

[Darter6]

doesn't look super rich to me

I agree

 

[BSB67]

Check fuel pressure and try a volume test. Hooking up a fuel pressure gauge and doing a WOT test would help. Probably not a carb problem.

This. You need to start here. Your lean WOT might be fuel delivery and not jetting. Get a WOT fuel pressure reading and report back.

 

[lewtot184]

This. You need to start here. Your lean WOT might be fuel delivery and not jetting. Get a WOT fuel pressure reading and report back.

You got me doing this. It's truly an eye opener..

 

[Geoff 2]

Do the basic checks first:
- float level correct [ 7/16"]
- are the sec blades opening fully
- fuel delivery. A 300 hp engine will consume about 25 gal/hr. Estimate the hp & measure the fuel delivery.

Further comments:
- while it could be the n/seats restricting flow, I doubt it; if the fuel pressure is very low, it could be the cause. Get some Carter AFB/AVS 0.101 or 0.110" n/seats to eliminate the possibilty. Set the new float level to 15/32" or 1/2" respectively.
- the most likely cause. I have seen pics of some Edel 750 AFB carbs that had a bullet nose end to the sec booster emulsion tubes. These had a small hole in the end which was smaller than the sec jet & in effect became the sec met jet. Simply enlarge this hole so that it is larger than any sec jet that is likely to be used; this ensures the jet does the fuel metering, not the emul tube entrsnce hole.