Thanks man. And I updated the original post. Any V8 system will work, but the 454 throttle body will definitely be better.
And yeah, for the Pimpala. Not anytime soon, of course. Just now sorting out the kinks.
The basic throttle bodies only move about 450 cfm or so, so they only support about 250 hp in stock trim. But the 454 TB is good for 670 cfm and, with upsized injectors and fuel pressure, can support 400+hp. I'm only needing to feed 385hp. After reading up on this I've realized that they are very basic, but well performing systems. The few conversion I've found solid info on typically gain about 3-5 mpg, increased throttle response and have zero complaints. And it's actually pretty affordable. I think I can piece a solid system together for under $400. I know a tuned port system (TPI) would be way more advanced, but it's also more complicate than what I want to own and,well, it just won't fit under my hood. Very neat little systems actually.
If I get this sorted out on the car I might tackle fitting one to the mighty 300, too.