bolt pattern

Hey guys and gals............1990 base caprice 305 TBI what is the bolt pattern ? is it 4 1/2 or 4 3/4 ? I've been told to messure centre stud to centre stude and centre stud to other side of stud.Wich is right ? I also found a build sheet in my car !!!! i was told by a parts manager here in Ottawa Canada only "special" cars now days have build sheets in them ? He told me its either a cop car or fleet use... i know its not an 9C1.Any one have any idea ?

What bolt pattern are you referring? Wheel? If that's the case, it's 5 on 4.75. 5 on 4.5 is Ford.