transmission that goes with 360?

If you intend on using a big block you will need a big block 727. Yes there is a difference in the mount between the big and small blocks. As for a small block a 727 or a 904 will work. The 904 is a lighter version that requires modification for hard abuse. The 360 is different from the 273,318,340 in the way the engine is balanced so the flex plate is important to get the right one.