Perseverance.
Remove the nut and wheel bearing. Try putting one or two flat bars between the drum and backing plate and apply pressure while you tap around the brake drum. You can fracture the drum if you hit it too hard. Hammer and wood block are good. A friend to help, also good.
Use one or two lug bolts screwed in the drum and a long pry bar to rotate the drum.
Brake drums from 36-50 will fit your truck BTW.
