"a worker with arms as thick as Sylvester Stallone's"
Sylvester Stallone
Creative Commons Attribution Share AlikeSylvester Stallone - Credit: Gage Skidmore

Sylvester Stallone is one of the most successful actors of all time, famous for his roles in the Rambo and Rocky series. The narrator's comparison of the worker with thick arms to Stallone is appropriate; he regularly brandished his biceps in his roles.

The interesting issue here is that the narrator is making a reference to Stallone in hindsight, as he would not have been well known in 1971 (Rambo didn't come out until 1976). This is evidence of the narrator reflecting on his experience, which also helps to classify the novel as Scar Literature.