Rear end ratios....What can I really change mine to?

[65Guy]

well with a gear that short you problly have a series 4 carrier which is the part that the ring gear bolts to. the lowest you can go with a 4 series is 3.73. if you want to go lower you will have to change the carrier. and im pretty shure any thing from a 65 all the way to a 87 if its truck 12 bolt it will fit, and if it is all stock you might consider blowing it all apart for a full rebuild. Bearings and seals.