Here you can see the 5.0L forged crank installed in the block with no grinding needed. Thanks to the special combination of crank, rods, and pistons, you could put this kit in your 4.0L block at home. An upgrade we went with was this girdle which Chrysler installed in later Jeep engines. We found a used one to add to our motor, and then found out they are available as a kit from 505 Performance as well (including new studs and nuts for mounting). The girdle stiffens the bottom end of the block when under load and helps keep the main bearing caps better aligned for less wear on the lower-end bearings. With the power levels we were shooting for, every little bit helps, but the girdle would also likely increase reliability of a lesser-built engine as well.