I was just wondering what I have here? Its definitely an 8 3/4 rearend, but it has a 5.5" bolt pattern? (I have seen plenty of 4" and 4.5") But this is 5.5" bolt pattern. It measures 43.5" center to center on the spring perches, and overall 58 1/4" flange to flange. It also has what appears to be 12" O.D. drums? Im guessing some sort of truck rear? I have not taken it apart yet to see what gears it has, but it does have a 489 center section...Anyone know what I might have here? Thanks in advance.