If someone threw the Raptor project into my lap, and I had to move the overall project forward, I would pull everything aft of the firewall, and install a Continental TSIO-550 of 350 HP, remove everything not essential to flight, and test and refine the airframe and flight control systems.
If the results were reasonable and salable, (big ifs) I would add basic interior and an installed oxygen system, and start limited production.
I would find one of the auto engine conversion proponents that continually proclaim the superiority of auto conversions for aircraft, and give him the Diesel to play with, or either sell it to the local bus company. If he were to get the entire system running reliably on a test stand, I would look for a customer to install it.
BJC