I have a posi unit from a 8.5 inch rear but cannot identify it as a 2 or 3 series carrier. I have read what casting numbers should be found on it but they are not there. the only numbers on the unit are 725 and they are in large letters on the ring gear flange. If anyone knows hoe to identify it by measuring the ring gear flange offset i could identify it that way. I currently have a grand national rear in my 87 ss and the rearend is starting to get a slight whine so i want to use this posi unit and go from 3.42 to 3.73 gears when i do the rebuild. The motor really pulls hard to around 5500 so i think it could benefit from a little extra gear. This is a daily driver so i dont want to get to low with the gear but it needs positraction. Any help would be appreciated.
