Lower priced Power lok, sure grip units on Ebay.

I bought my differential on e-bay motors, it is a sure-lok diff. I bought the bearing kit for a 742 case from summit (complete kit) with Timken bearings. Put in 391 gears and it runs great all is working as expected. In my opinion they are ok. I can't say great cause I only drove it for the break in miles, but it did do great hole shots with no problems yet. I guess I'll find out with more miles. The seller on Ebay said they would take care of any problems as long as I used new bearings and races. They gave me a direct phone number.