In June I towed a trailered '41 Chevy from Wyoming to Virginia with my S/C S-Runner. Never fell below 60 in the mountains and that was without putting the pedal to the floor. No overheating problems, but you have to watch for pinging in areas where you can't get 93 octane. In that case just ease off on the hills and don't accelerate as hard. MPG was 10 - 14. Note: make sure your entire hitch set-up is rated for at least 6,000 lbs although the truck is only rated for 5,000. The class III hitch and the ball should say 6,000 lbs. I found out the hard way, but that's another story.