......7s is the goal as in a' point to reach.The thread was about the importance of the 28sVS THE 31S BEING THAT IT IS AN AOD. like I said before"All I want to is get the rear end taken care of before I go checking off the engine/transmission parts list". If i don't know how fast I want to go and how much I can afford what Is the point? My track lok is worn, so while im in there I might as well get it done once and for all. I never said I want to rebuild the rear end SO I CAN GET into the 7s, if i would have said I want to rebuild the rear end with 4.10s what would be asked next?"how fast are you trying to go and much can you spend?" right? that's why I said it that way,my grandma knows that it takes more than that.