There is a way to establish an absolutely accurate top dead center mark for a specific crankshaft/flywheel/harmonic balancer combination, one we race engine builders have been using since long before I was born, but it's not something to explain with a keyboard. I learned it from my father, who began building engines in the mid-1930's.
I have a complete column shift linkage, including the lever arm box, that was left over from the 4 speed conversion. We might be able to do a little horse trading, as I would be able to take what's left of yours and machine a new top piece to complete it.
