Mopar Muscle Association UK

I need a new front wheel bearing for my 69 Runner.The guy at the spares shop wants to know what size brakes I've got.
Where and what do I measure?

Measure across the inside shiny face of the drum or, look on the outside face and there should be a max size, i.e. max oversize 10.060", the first part of the number is the size of the drum........

Thanks Alex.