weltertm, i went from 235-75-15 to my current 225-70-15, and added about 200 rpm at 60mph. thats with a th350 3 speed automatic.
the 225-70's are right at 27 inches tall, and the 235-75's were about 28-28.5 tall.
hope this helps.
and if you look at my web album you can see before and after pics..
leonard
