Thanks guys for the help on clearance height,I can now make my vacation. I just measured my truck under the framing on my garage door. It just happens to have a 6 foot 8 inch frame height which is what I needed for the water pipe clearance under the bridge. My sport has cab lights and 265 stock Michelin tires. The highest part of the cab is just behind the cab lights 6 foot 5 inches. My cab high topper at the back is 6 foot 6 inches (truck is a little higher in back with no bed load. I still plan on bringing a 6 foot 8 inch 2x4 to check the bridge clearance,but at least I know I can slowly go under anything over 6 foot 6 inch. I posted this as a new thread since the info might come in handy for someone.
Rock
Rock