Hello all. I need some advice. 1st let me start by saying I have been on the board for a while researching for my 71 skylark build but this is my 1st post. I need to upgrade the rear end in my car to support 550 est hp. Engine wise its a gen 4 6.0 ls swap with the basic upgrades, trickflow performance cam(elgin sloppy stage 2). Headers, etc. This same build was done for hotrod mag and produced 514 hp. This is a street car the might see the track once or twice just for bragging rights lol. Whats the best way to go to build the rear to support this or should I just get a 9" ford rear built? I do plan to go with 3.73 gears and a true trac posi. I'm sure these questions have been asked a thousand times but thanks for Any help that can be provided.