On a 5.3 it should stall around 2300-2500rpms.
It is a direct swap.
There are a bunch of guys running them behine 5.3's, 6.0's, 5.7's and I haven't heard of a single problem yet.
I've got one behind my LS1 5.7 and it's been great. Really pulls hard from a stop.
For the price, you can't beat it if you ask me.