42RH / A-500 in a Duster with pictures.

it'll handle it. I'm hitting one with almost 600hp. I had my input and hub cryoed, just to give it a bit more strength. Currently running 4.56s and have hit it hard through all the gears. Lockup is not necessary, but even in lockup, it holds just fine.
Just don't hit lockup under extreme throttle/acceleration, it is only a single disk.