Yes, the unbalanced torque created at the prop shaft, and reacted through the engine mounts, is real. And pilots have been taught this and P-factor for ages. There's also the explanation that the left wing has more "washout" to react against the roll.
But when the numbers are examined, and the engineering designs reviewed (wings are in fact symmetrical), then unbalanced torque is pretty minor compared to the propwash vortex striking the fin. This is further reinforced by experience in nonstandard aircraft designs with the fin (or most of it) below the thrust line; LEFT rudder is required at takeoff!
Check the fin of your plane; chances are the fin LE is slightly offset left to trim out the yaw resulting from the prop vortex.
40+ years ago there was an outstanding article in EAA's Sport Aviation, examining these and other aspects of what we've always called "torque".
Last edited by barit1; 31st October 2014 at 13:14.