Whats the problem with running a C6 on the hiway? There are littoraly millions of C6s running up and down the hiways and byways. Probablly the strongest automatic transmission used in passenger cars and light trucks.BBsteve said:ok... im glad to see that you ca do some hwy driving with the c6. i was going to run either 3.55 or 3.73s. any ideas of what rpm id turn at 65mph?