U650 Tractor v8 (Subdivision ready 3D model) is available on CGTrader for $59. Original author: dragosburian. Specs: 278623 polys, 368795 verts.
BLEND (Blender, filesize: 13.9 MB), OBJ (OBJ, filesize: 11.7 MB), FBX (Autodesk FBX, filesize: 17.1 MB), STL (Stereolithography, filesize: 9.95 MB), DAE (Collada, filesize: 15.2 MB)