Some quick info - swap kit for the 7.3 into the 6.2 truck is about $4500. You need to provide engine assembly (obviously), a throttle body to filter tube with MAF mount (not too difficult), a setup to attach the exhaust manifolds to the rest of the exhaust (any exhaust shop can probably build this), and re-route the trans cooler lines (also not difficult as you could just bend and make new ones). Figure around $1000 for all of that. There's a few misc. parts you'd still need from the 6.2 as well. The tuning is about $1500, uses the stock 6.2 PCM so that everything else via the CANBus still works as stock in the truck.
A stock 7.3 without any aftermarket modifications will do 800HP @ 10PSI, and still be pretty "safe." From what I've seen you can get 700HP out of a stock 6.2, but it's not going to last very long, at which point to push 700HP reliability, or go anywhere beyond that, you need to build the engine. If we are talking a Livernois built 6.2 for $22k minus supercharger, you're still only talking about making 500HP. The full 7.3 swap, assuming you pay around $7000 for the engine, and with a Whipple kit, would put you around $22k with 800HP. As EricM above stated, you're not just talking way more power at that point, but also an engine that has full aftermarket support, is lighter, smaller, and way more displacement. It just doesn't seem like it's worth trying to really push on the 6.2 at that point.
