Originally Posted by w7ts
The specs for my Classic 31 say "height with A/C 9' 7 1/2 "
Just remember, it will vary according to load, height of a/c unit, and whether you have installed new axles, and what the starting angle of them is.
A handy "old timer" truck drivers' trick is to remove most of the air from the tires, and go under the low obstacle on the shoulder. This will give you nearly a foot more clearance, though carrying a compressor to re-inflate is a must.