A little Turbo Selection Help

Looking at the specs for that, I think they are being very optimistic when they say “up to 420hp” for that size compressor. That being said, I think you’re in the ballpark for a 225 on the sizing. I hate internally wastgated turbos and I’d rather see you use an external waste gate but that adds cost and complexity. What is your hp goal? That is the most important piece of the puzzle in turbo selection.