318s are internally balanced, or neutral balanced. 360's are externally balanced, and require a special weighted balancer, and a special either weighted flywheel or weighted converter. That's because "that's the way" Chrysler added the weights.........to the converter instead of the flex plate.
"Handily" BM makes several aftermarket flex plates to allow 318 neutral converters to be used with a 360
Magnums are weighted differently than are LA 360s, but on them the weights are on the flex plate. Also the bolt pattern on Mag converters is symmetrical, rather than the one index bolt "off" with older LA, which "keys" the converter to the proper place re: the engine crank.
