Is the machine worth the repair? There is alot of labor pulling a motor on an old clark. Its been a while for that old of a truck, but, hood, radiator, fuel system, linkages etc. are removed 1st.

Next check to see where the hydraulic tank has a large feed hose hooked to the pump. If the hydraulic pump is attached to the engine, you must empty the the 10 gallons of oil.

Front engine mount (rear of the truck) nuts are taken out. I usually use a "come along" rachet cable hooked to the over head guard and pull the front of the motor up, caulk up the trany w/ wood, remove the torque convertor bolts from the fly wheel( automatics), then trany bolts. Rock the engine while pulling it backwards.
Come along the engine high enough to pull it out w/ another machine, or engine lift, or by hand if you have help. There maybe a thing or to that I forgot but those machines are a real pain.

Also when you been to apply your skills on an old piece of $#@*, you have to contend w/ the domino theory. Things that are ready to break, are going to break after you touch them.

Unless the machine is worth that kind of time, I probably wouldn't do it.