I assume that the rear end in the mercury gm , crown vics are the ford 8.8 inch but I am not sure could anybody help me ?
I was wanting to know so I could put a posi trac in it. thanks.

 

Ford makes Trac-Lok rearends... and they are 8.8... check tag on rear cover... it will tell you the size and ratio... or look up code on driver door... look up the number/letter under the AX code on the sticker to tell you what it is