I looked at several lunch box lockers, for a long time. I kind of though I was going to get a powertrax no slip. Then my rear end started making a lot on noise. So I asked a bunch of people at the car shows that I go to, what they were running. Most of them said, an Eaton trutrac. One of them is using it in his 68 Mustang get 500. He is pushing 865 HP @ the rear wheels. Of course he is running a Ford 9 inch rear end. I also asked about rear end gearing. Running the 275/60/15 tires, and a 4L60E, they were all in agreement that I should go with 373 gears. Man we're they ever rite. It cost me about $1200 to rebuild my rear end my self. All new bearings, races, seals, carrier( the Eaton trutrac) oil, and even new wheel cylinders for the brakes. The trutrac works flawlessly. It is a true limited slip differential. It works on helix gears. There are no clutches to ware out, no springs, and you don't add the additive like you need in clutch systems. It is perfect for the street. If you use your truck for off road mostly, there may be better choices out there, IDK. Also, when I tore into my rear end, I had broker the bearing mount area off of the OE open carrier, so I would have needed another carrier anyway. Now, everything in my rear end is new. The only kicker was a week and a half later, I blew up the transmission. I had to have it rebuilt. I had a shop, do a performance rebuild. HD master rebuild kit, Corvette survos, shift kit, ECT. That was $2800. That was about a year and a half ago. It's holding up grate.
You must be registered for see images attach