I too kept getting startled when I was towing The Ox down from Oregon behind "Big Red" (77 C20, now demised)... I'd glance in the rear view mirror and see a huge grill bearing down on me... then realize... what it was..

My 454 got 10mpg empty, and 7.5 mpg towing.

Another quality post.
Real Trucks Rattle
HELP! The Paranoids are after me!