A wideband o2 read out is a great tool for setting up EFI and carbed engines.
on a carbed engine you will be able to set idle air/fuel ratio by setting the idle screws, set cruise and power ratio by changing main jets and/or power valve.
i use them the most on efi engines and they work just as well on carbed engines.
put it on......you might be surprised at the results you get for idle/cruise/power conditions.
a stock engine should have around 14.3:1 - 14.7:1 @idle
14.7:1-15.0:1 @cruise and around 13.0:1-12.0:1 @wot.