I wanna put posi on my car. What is the exact part name for a posi rear end for a 1970 mach 1, i have a 9" rear with the hump on my mach 1..what am i looking for and does anyone know of a good place to buy this....

 

Trac-Loc limited slip

 

truck junkyards sometimes have them .. i got mine from a truck ..

 

I thought that was original equiptment for a Mach? if you don't mind aftermarket companies I would recomend the eaton trutrak, i put one in mine, and have Bern very impressed it's smooth and doesn't occasionally clank like my Detroit locker does in my truck and it doesn't have any clutches that will need to be replaced like a factory posi, also it was very affordable around $400 only thing is is that it's not recomended for anything over around 400rwhp, I got mine new off eBay with warranty, I hope that helps.