My 55.2 gets about 20 on the highway with a bit of tuning on the carb. These old carbs ran ridiculously rich with stock jetting. I get less than that in normal driving, where i start it on the weekends to run across town for one reason or another. In normal running, cold, choked, less than 5 miles at a time, I probably get about 10 mpg. I don't keep track there.
Devin
