does anyone know?

I have a 65 barracuda which i just bought anson sprint rims 15x7,i fit the rims on the front drums and they seem to fit fine.Now here is my question ,the lug studs seem to be to short so ive decide to, at this time just get new drums all the way around.How do i measure the drums so i order the right ones ,ive gone with a measuring tape and seems to be 10 inch drums but i would like to be sure.


thanks