Nice improvement in fuel economy!
The restrictors in the casting are easily "spun out" with a drill armed with a drill bit that just catches the edge of them. I think it's right at .111-.113".
We have drive in and screw in restrictors for the idle down channel, and main airbleed locations.
A wide ban is a good investment, but really not needed if you know how to tune. The best tuning tool is to make very small changes, then observe the results over several tankfuls of fuel. In many cases, you will know quickly if you went in the wrong direction, but when you get really close, it may take a few miles to know if you've improved things or not? At the end of the day what really matters is how the engine performs in all areas, and how much fuel you use for "normal" driving. From what I've seen here, folks drive themselves knucking futs chasing the wide-ban 02 sensor around, instead of paying attention to how the engine works and how much fuel it uses....FWIW......Cliff
PS: don't forget about distributor tuning in conjunction with carb tuning. Leaner mixtures are difficult to burn, and do NOT always produce improved results or fuel economy. It takes earlier ignition timing in many cases to effectively burn a leaner mixture.....
