LS powered Duster, Abomination or Go For it!

If he already has 5.3, maybe. That will bolt directly to a GM o/d trans (that many here have swapped to) a set of conversion mounts, ….
Admittedly, I was really thinking of build cost.

Custom exhaust, mounts, headers, computer and wiring, etc stuff adds up quick. Sell the 5.3, buy a small block mopar, and save some money and a lot of aggravation. Just my two cents.