You want to use this truck as a daily driver and tow vehicle, right? Even 12-15 PSI is a lot of boost for a daily driver; something more on the order of 8-10 would yield huge performance gains without disproportional decreases in reliability. Above that level, it becomes prgressively more and more like juggling hand grenades; 20-25 PSI would be pretty much a race-only engine and could allow as little as 10-12 hours of run time between rebuilds.
If you really want that kind of performance (5-600 BHP) forget about the 300. For that matter forget about a SBF/Windsor as well. The only recent Ford engine that's going to give you that kind of performance in a reliable, streetable package is the 385 series. A moderately built 460 will produce a reliable 500 HP / 500 ft-lbs; a 514 will just as easily make 600.
Frankly, your goals are simply unrealistic. That level of performance with any engine makes a terrible daily driver. You give up way too much drivability and tractability to gain performance that 99% of the time you simply cannot use. If you aim for something in the 300-350 HP/TQ range you will have an excellent tow vehicle and a much more user-friendly piece of transportation. Just my $.02