My personal opinion of doing this, is it's a waste of time and/or money. Just use a 225 motor. Easy/Peasy
Unless you are racing, and the low deck slant gives you an advantage. Slant Six racing rules allow the low deck engine to run the next lower weight class, then the same vehicle with the high deck engine.
I do believe you missed your flight. My point was piston CD and piston availability to get the CR up for street, not racing. A well built and tuned 225 should perform well and get good fuel economy.