This is a bit late, but for other people who might read this thread: We have traveled thru Yosemite via highways 140 and 41, and on up over Tioga Pass on highway 120.
There are 4 tunnels in Yosemite. 3 on Big Oak Flat Road, 2 short ones and one about 1/3 mile long. The Wawona Tunnel on highway 41 is about 1 mile long. Be sure to stop on the valley side of the tunnel for a geat view. Watch for pedestrians, not watching for you.
All four of these tunnels are passsable. We measure 11'9".
But we did hug the center line!!