You can use an 81/82 LTD bottom end. An early issue of Sno Goer magazine had this to say...
"The Kawasaki Interceptor engine was in a unique position of probably being below par. As soon as word leaked out last season that the new 530 parts would bolt directly on the 1981 440 LTD motors, Kawasaki parts distributors were emptied of 530 cylinders. Not even the engineering group could get new cylinders for the 1983 Interceptor entered in Shoot-Out III."
Pretty sure both 81/2 LTD and Interceptor bottom ends share the same X - code serial #. Obviously, an Interceptor bottom end would be ideal, but the "bathtub style" LTD bottom end will work. Wondering if any other members can add to this.