Here are a couple of pictures of my FT-897D with an LDG YT-100 antenna tuner fitted inside.
In the first picture you can see the rear top view of the radio. As you can see, I added a couple of binding posts for wire antennas and a push button to activate the tuner. I also plan on adding another UHF connector for coax-fed antennas in the near future. I am just waiting for the connectors to arrive.
In the second picture, you can see the rear bottom view, with the four phillips screws that hold the tuner board in place. The back cover is raised a couple of milimiters so that the tuner has enough room inside the battery compartment.