this.Honestly, it's difficult to make a naturally aspirated 38 to go above 300. The mods would be extreme, such as very aggressive camshaft, and a high stall converter to go with it, extensive head porting by a professional who can test flow on a flow bench, high compression pistons, a full balance job, and probably bored out. Even with all that, you'd be hard pressed to make 300 whp. Meanwhile, you could do half that, and make 300 hp relatively easily if you keep it supercharged. Plus, it'll be twice as fun to drive.