I have a Edel 650 AVS with manual choke. Using the tuning book that came with the carb, I could not dial it in correctly for my altitude of 5000 feet, was running way to rich.
So I bought an Edelbrock 6593 Air/Fuel Ratio Monitor kit. Was easy to install, and was accurate enough to tune every circuit in the carb: idle, transfer slots, main jets, secondary jets, and accel pump. I'm very pleased with the results. Bought extra O2 sensor fittings for the exhaust manifold so I can use the sensor on other vehicles in the future....like my thermoquad for the 360 I'm building.