help- do i have 9 or 10 inch drums, and what about shoes???

I have no idea if i need 9 or 10 inch drums, when going about 40plus and i hit the brakes the steering wheel shakes very similiar to when you need new rotors on a disc brake car. Im not familiar at all with drum brakes, so do i order 9 or 10 inch drums and do i need to order new shoes as well? any help is appreciated. my car is the stock 5 x 4 bolt pattern. Thank you.