360 into a 318 car ??

Simple. Either get a torque converter weighted for the 360, and make sure you have the proper balancer for the 360

or else buy a B&M weighted flex plate for the 360. (These are made for this purpose)

And by the way, Magnum and LA 360s are weighted differently from each other, so make certain you get the correct one, there.
I agree,He stated 74 360 so is an LA engine...will need the drivers side motor mount also hopefully it came with it from a car,so would probably be the spool type mount,if going into a pre 73 car then motormount would be different bracket and biscut style