<VV> Leaning Out the Midrange (Long and Boring)

[Mikeamauro at aol.com]

OK, as I stated in my first post, I'm on a quest to improve fuel economy  
with my 67, 110, factory air, PG, dual exhaust, coupe. Narrow band O2 sensors,  
installed one in each bank, indicate rich in the midrange (11-to-12- to-1 A/F  
mixture...thanks Bob for straightening me out on the terminology). This is 
with  .049 jets. Also as stated, the poor fuel economy (I'm all the way up to  
16mpg) cannot be explained by any mechanical or tuning deficiency. For the  
doubters...completely rebuilt; average 2-3% leak down rate; 40+ forged; zero oil  
consumption; .032 quench; 9-1 compression; advance curve verified; valve 
timing  verified & initial @ 17; Safeguard; Allison/Crane; LM carbs (with  
enrichment); 260 cam; everything is all new-new-new  as of about 8,000  miles. No 
peristaltic drag-- I can push this car with my fingertips. Is equipped  with a 
torque converter modified by Hughes Performance (stall increased by 250  over 
stock); 327 rear. Car runs great...lots of zip, but guzzles gas. 
With that out of the way, and realizing main jets have little to do with  
fuel flow....except near or at WOT...I need to fuss with the midrange metering.  
I'll be purchasing wide band A/F + RPM input diagnostics equipment (I've got  
three Vairs, all likely running richer than necessary in the midrange). So 
far,  it seems I have the following options: lower float level (have already done 
so);  try different clusters (this sounds a bit like trial & error); or, the 
best  area to work with seems the emulsion tube air bleed. I'm a little  vague 
with the working of that assembly, and would like to find full technical  
documentation on the stock carbs. I actually had such a document, once, but it  
seems to have lost itself. The document of which I speak had some really  
detailed sections, with explainations of each fuel-air circuit in detail. I  may 
even have, at some point years ago, downloaded said item. Is this ringing a  
bell with anyone? I've looked in Clark's and cannot locate.
Thanks,
Mike Mauro