The most I remember curling was 80lbs. DB's for reps seated with perfect form and 90's for hammer curls with some swinging.
BB curls hurt my wrists, so i never went heavy on those, i don't remember curling more than 155 on a barbell.
My arms were 19" max when I weighed in the 240's.
Today they are about 17" and i curl the 65's pretty easily, but my bodyweight is down to 193.