To many variables to use a IC to measure the A/F ratio
with any where near accurate readings... a few thousandths
thicker coating on the header will give you 30*
different reading, add in the center cylinder tend
to run hotter.... just use a A/F meter or invest in
EGTs, I have both but now days use the EGTs (on all
8 cyl exactly 1" from the head surface) to set the
flow on the intakes I make and the A/F for its job