Caprice wheel specs? 1987

Does anybody know or know where to find the specs on the regular 15" wheel that came on all these box Caprices? Offset, backspacing, etc. Thanks!

And is the civilian cars' lug config 5x4.75? Or 5x4.5? 9C1 I know is 5x5.

Can't remember the offset (3"?) but the wheel pattern is 15x6, 5 on 4.75". The Fords are 5x4.5".

here is a link but no off set stated http://www.roadkillcustoms.com/hot-rods-rat-rods/Wheel-Bolt-Pattern-Cross-Reference-Database.asp?Makes=Chevrolet+&Models=CAPRICE+CLASSIC

Can't remember the offset (3"?) but the wheel pattern is 15x6, 5 on 4.75". The Fords are 5x4.5".
Thanks Silicon (I figured you'd be the one in the know :tongue:). I have my stock wheels off the car, so for backspacing do I just measure the distance from the back of the lug hole area straight out (same direction as axle) to where the inside edge of the rim would be?