I had the same question on the installation of the torque converter and flywheel on my 54'. What I noticed was there was a painted white dot or stripe on the flywheel which I had dismissed when looking for the "x". As I recall from searching in a late 50's chevrolet shop manual reference is made to this painted mark. Coincidence or not - not sure but I lined them up anyways. Take a look on your flywheel as well...
John