Is it this one - Link
How much power are you making?
Have you got a link to a cap strap kit? I don't know what that is. Same with the lunchbox locker.
My Charger is currently a very base 72 318 auto. The 318 is not going to stay stock and may not stay at all, but at any rate I'm not shooting for more than 500 hp MAX at this time as that is twice as powerful as anything I've driven before. I don't want to do the Cars and Coffee fishtail of destruction. I've got to build up my skills before I'm ready for 900 hp in a car that doesn't drive itself.
I found a 29 spline Auburn diff a couple days ago, before the power went out and ate my work. The specs didn't say how much power it was good for though.