Tuning a vac secondary carb....wideband AFR thoughts

[idrift]

I've been tuning a holley 670 street avenger with a wideband afr gauge.

So far, I'm running about 14.5 at idle and 14-15 at cruising at 55 mph which
is about 2500 rpm. From 2500 rpm going to wot I get the momentary lean
shot I'm guessing from the acc pump, then she runs about 13.5-14.5 for
about a second to two, then I go to about 10.5-11. Cruising at 70 mph
which is 3200 rpm, I run about a steady 12.5

I am guessing what I am seeing is that the secondarys need to open sooner
which is a lighter spring but then I run too rich at highway speeds. I could
jet leaner but I don't think that is it. Could the powervalve need to be
changed to a high flow to handle the lag?

I think if the readings I have a pretty good for a carbureted engine or can
the be tweaked more?

 

[crackedback]

I would disconnect the secondary and wire it closed. Tune the primary and get it right, then go at the secondaries.

 

[idrift]

I am thinking the secondaries are cracking open at the 3200 rpm and that is
why it starts running richer but I guess I could at least rule that out one
way or another to know for sure.