/6 904 to sb 904

No i am putting in the 318 with the Schu. motor mounts. are you saying that I can use the /6 torque convertor in the other 904? what are the pros and cons of this? ...Just so I understand this Both convertors ( /6 or v8) will fit. There the same? which will give more torque? my 8 3/4 will have 323 and later maybe 391 gears. Will the /6 one bolt right on?