What is the difference between a flywheel for a 360 and all the other small blocks

From Mopedia

The 360 is externally balanced, which means part of the weight used to offset the weight of the piston and rod combo is added external to the engine block. In this case both the balancer and flywheel or torque converter have weight added to them from neutral balance. Most Mopar cast crank motors are externally balanced, the 318 being the exception.