340 Crankshaft balancing.

I bought a 70 X code engine while back that had been taken apart and have finally gotten around to looking at rebuilding it. My question is I checked the numbers on the crank and it shows to be a 73 model crank so do I need to have this balanced or all the all the same? Or do I need to find a 70 model steel crank to use?

Also this engine had an automatic behind it and it will be going in a 4 speed duster. Any issues with pilot shaft bushing or anything?

Thanks for any reply!