66 Valiant Signet has a 360LA engine - what do I need to know?

Perhaps, but I thought that would be about right for neutral balance of the part itself. I think some aftermarket flywheels offer an attachment for the counter weight as needed by the application. I could be wrong, though! I had only read that the 360 with the cast crank needed external counter weights on each end? But maybe with the heavier flywheel that's not necessary?