Sure, it's doable. With 10:1 compression you'll probably want an intercooler even with only 6 psi boost. If not an intercooler then maybe a boost referenced ignition that retards timing under boost.
I'm just taking a guess at the numbers here, but with 6 pounds boost you might gain 32% power. With 6 pounds and intercooling you might gain 38%. So working backwards from 600 hp with no intercooler, you'd need around 455 hp naturally aspirated. Or 600 hp with an intercooler, you'd need around 435 hp naturally aspirated. That's doable with a 390 and decent heads.
I'd guess a 390 block will live at 600 hp for some time, especially since the blower will allow it to make the power at a lower rpm. If it were me I'd do a partial fill of Hardblok on the block. Stud the bottom end or crossbolt it if you want to get fancy.
Here's a guy selling just such setup. I don't think he'll mind me posting his email and ad. I don't know him so this is just FYI.
"I'm located in Albuquerque, NM.
If I part with the supercharger, I would like to sell it as a complete package. It's not show quality, it's been used and regularly maintained in a '72 F100.
When I bought it, I paid a little more than $2K for it. Total cost with the Holley and materials for the setup came to a little more than $3K.
The complete package includes:
1. SN93
2. Mounting bracket (will not work with a power steering setup).
3. 2 pulleys, 5 psi and 7 psi respectively.
4. Blow thru carb hat.
5. Holley 650 cfm double pumper, with extra jets.
sean.brady.ucr@gmail.com"
Anyway, those were just some thoughts.
paulie