Rich 10:1 on primary circuit

[1983zsled]

I have done a little research on air fuel ratios for Vortec heads.
It seems most agree that 12.5 to 13 to 1 is the best for power.
I'm pretty close to these now so I will fine tune from there.
I use the car to idle to shows and just general driving.
I only hit the track once in a blue moon so I'm not going to get hung up on it.

The lean APT is only in OD and if I just barely touch the pedal...I mean barely touch it. The A/F leans out to over 17:1.
I think it's pulling fuel from the idle circuit only and that's why its so lean, not enough of a drop in vacuum to enact the primaries?  The engine is basically idling along and I don't think it will cause any damage?

 

[Shark Racer]

Throttle angle too will put you on the primary circuit. It's interesting that it leans out though as you hit the gas pedal. Have you got enough accelerator pump shot? Are you on the inside or outside hole?

Can you feel anything when it does it, or is it just something you see on the gauge?

[1983zsled]

I'm just barely....I mean barely touching the pedal to get the real lean reading. If I push just a little more the accelerator pump comes in and richens it up. It is more of what the gauge reads than an  issue with drive ability. There is no lurching, bucking, or shuddering that you normally get with a real lean condition at part throttle.  I have had this issue before with other q-jets I have built and I think it may be quite normal. I have read others with wide band sensors reporting similar findings.   

I will drive it for a bit and see what transpires.
Thanks again to all for their help!
 

[TommyK]

As long as it doesn't sneeze when going that lean I wouldn't worry about it. You can't hurt it with virtually no load on it.