Try "Automobile-catalog" for info on your truck's specs. Western power one's usually have either large rear body's or hydraulic platform on them. So likely HD springs ect.
I have a 2000 defender 110 special edition, which has been off the road for number of years, head gasket gone. I am currently trying to find out what the "Special Edition" spec is. It was once a western power vehicle and was told they have higher...