First of all, get a pressure washer or steam cleaner and ruthlessly clean all the dirt, grime and grease from every inch of the engine, frame and transmission.
Remove the hood.
The radiator frame has a top piece that unbolts with three bolts on each side. Take that off and see if the next frame has been cut out for clearance. If not you have the choice of cutting it away or dismantling farther. Also take off the front pan over the grill area.
Use a 2 Ton hoist, with the longer lift arm.
If this is a four speed take it out first, use a trans floor jack. The sm420 is really heavy and more so with a PTO.
Remove the engine mount bolts going through the frame on the rear mounts and the two going through the frame on the front. disconnect all the other lines and wires and pull it out
