<VV> Leaning out the midrange

[NicolCS at aol.com]

If you are using a heated O2 sensor, it should be able to detect a mixture 
that is so far away from 14.8:1.  If the sensor isn't heated, I wouldn't be too 
sure that it's accurate.  Your target cruise should be over 15:1.  Are you 
running "power valve" carburetors? (yet?)

Why are you concerned about jets smaller than .049?   If I'm not mistaken, 
your heads were modified for high-swirl and with the better mixing, you don't 
have to worry about pockets of lean mixture detonating.  The whole point of 
high-swirl is to improve combustion efficiency and the benefit is improved fuel 
economy through smaller jets.  Smaller jets are the desired result. If your 
gauge is accurate, your engine certainly isn't running "lean"
C. Nicol