hey ive hear AU engine can fit in ea falcons upto el but would like to know what would hav 2 do for a lower year falcon like a xb. need different crossmember? engine mounts?

If you use ea-ed engine mounts on the AU block they will be located in the same location as the mounts on a 250 crossflow. The sump on the AU sticks out a lot further than the 250 though, so anything immediately in front might have to be modified.