A motor plate is usually fairly easy to fabricate but it all depends on the details. Doesn't look like you have a lot of room in that chassis for a water pump so you might be forced into a remote pump. You'll need to lower the engine block in there and see which will work better. The factory Hemi mounts work best if there are frame rails close to the block. The Hemi mounts don't work well if the mounts have to be very long. A motor plate works better if it has to reach out to the frame rails since a motor plate is much stronger in the vertical direction.