i believe i may have found something. i pulled the drum on the Corona, it had "max 230.6 mm".and i measured it to be the ID size, this
Beck Arnley 083-0448 Brake Drum on Amazon fits the '73 celica and corolla @ 230.6 mm even though your Ebay link says the corolla max ID is 272.6. the beck arnley website says Max ID is 230mm even though the drum pic has 230.6mm. so i see a confrontation of ID and OD annotations and MM sizes. The amazon pic of the BA shows the total OD @ 11'', my total OD is a hair more than 10 3/4", hopefully the pics are an accurate display as well, the BA pic and my drum do not have cooling fins i noticed some other pics do though. I 'll look a little more but i may just have to take a chance on that BA drum from Amazon