Yeah, or if you don't want to go the d-max route why not a 6.4? They are not nearly as limited as a 7.3. The PCM allows for basically any rpm, injectors and pumps are simple to come by and cheap. Plenty of aftermarket support and even off the shelf billet heads if you want to he squirrelly. And on top of that it's a bed plate engine and has proven to be competitive with any platform out there. Plus tuning through h&s mcc is a snap.
Where and who is running the billet heads? Street or competition only? PM me if you want.